Article

R179H mutation in ACTA2 expanding the phenotype to include prune-belly sequence and skin manifestations

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Abstract

Mutations in ACTA2 (smooth muscle cell-specific isoform of α-actin) lead to a predisposition to thoracic aortic aneurysms and other vascular diseases. More recently, the ACTA2 R179H mutation has been described in individuals with global smooth muscle dysfunction. We report a patient heterozygous for the mutation in ACTA2 R179H who presented with megacystis at 13 weeks gestational age and, at birth, with prune-belly sequence. He also had deep skin dimples and creases on his palms and soles, a finding not previously described but possibly related to ACTA2. To our knowledge, this is the first report of the R179H mutation in ACTA2 in a child with prune-belly sequence. We think the R179H mutation in ACTA2 should be included in the differential diagnosis of individuals presenting with the sequence without an identified mechanical obstruction. Furthermore, as ACTA2 R179H has been reported in patients with severe vasculomyopathy and premature death, we recommend that molecular testing for this mutation be considered in fetuses presenting with fetal megacystis with a normal karyotype, particularly if the bladder diameter is 15 mm or more, to allow expectant parents to make an informed decision.

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... Williams suggests, however, the association of chromosomal anomalies (trisomy 18, trisomy 21, Turner syndrome, and others), as well X-linked recessive possibility of transmitting the disease; the latter would explain the greater incidence of disease in males than in the female [11][12][13][14]. ...
... Most cases occur sporadically in children with normal karyotype. There were authors (e.g., Williams) who have suggested an association with chromosomal abnormalities (trisomy 18, trisomy 21, and Turner syndrome) [14,15]. ...
... According to recent studies [14,15] rare association of chromosome abnormalities can be determinate in a prune-belly patient: ...
Article
The aim of this study follows the detailed evolution of a child diagnosed with prune-belly syndrome. This syndrome is a complex dysplasia, a rare pathology in children, characterized by the triad--the classic--hypo- or aplasia of righteous abdominal, cryptorchidism, abnormality of the urinary tract; also, it can be associated with pulmonary, cardiac, digestive, osteoarticular, and other malformations. Diagnostic criteria and etiopathogeny aspects are presented showing embryopathy and X-linked hereditary transmission theories as the most plausible, as proofed by recent genetic studies. Analyzing therapeutic aspects, it is stressed that medical treatment precedes or follows surgery, which cannot resolve urinary infection unless dysplastic urinary reconstruction is performed. Serious forms of prune-belly syndrome have a development and poor prognosis. Intrauterine and neonatal mortality is 20% and 50% in the first two years of life. The risk of urinary infection and/or lungs burdens the patient's clinical condition, allowing further appreciation on evolution of the disease. For cases solvable by plastic surgical reconstruction, as those who respond to medical therapy, differentiation will be monitored in territory and check-ups by the specialized consulting room from Polyclinic Health Center. Urinary infection relapse danger is permanent, requiring differentiated supervision. These case interest practitioners, by at least two aspects: the rarity of the disease, and complexity of dysplasia constituent, which has serious implications on the body economy.
... Both variants were absent from over 120,000 control exomes (14). WES in the index case failed to reveal pathogenic variants in genes known to cause megabladder, including ACTG2, CHRM3, HPSE2, LRIG2, MYH11 and MYLK (3,(15)(16)(17). (Fig. 3A). ...
... Other SM-related genes have been implicated in PBS. These include variants in ACTA2, a MYOCD target gene, as well as MYH11 and MYLK, in which variants can cause visceral myopathy, a phenotype encompassing megabladder (3,16). ...
Article
Full-text available
Myocardin (MYOCD) is the founding member of a class of transcriptional co-activators that bind serum response factor to activate gene expression programs critical in smooth muscle (SM) and cardiac muscle development. Insights into the molecular functions of MYOCD have been obtained from cell culture studies and, to date, knowledge about in vivo roles of MYOCD comes exclusively from experimental animals. Here, we defined an often lethal congenital human disease associated with inheritance of pathogenic MYOCD variants. This disease manifested as a massively dilated urinary bladder, or megabladder, with disrupted SM in its wall. We provided evidence that monoallelic loss-of-function variants in MYOCD caused congenital megabladder in males only, whereas biallelic variants were associated with disease in both sexes, with a phenotype additionally involving the cardiovascular system. These results were supported by co-segregation of MYOCD variants with the phenotype in four unrelated families, by in vitro transactivation studies where pathogenic variants resulted in abrogated SM gene expression, and finding megabladder in two distinct mouse models with reduced Myocd activity. In conclusion, we have demonstrated that variants in MYOCD result in human disease, and the collective findings highlight a vital role for MYOCD in mammalian organogenesis.
... Anonymized clinical and radiological data were analysed with appropriate human subjects research approval. Seven patients (Patients 1-6 and Patient 11, Table 1) have been included in previous publications focusing on clinical, rather than neuroimaging, features (Milewicz et al., 2010a;Richer et al., 2012). For the purposes of this study the primary radiological material was reviewed and analysed afresh. ...
... Patient 3 and Patient 13 have not had acute neurological symptoms but have global developmental delay, which prompted brain imaging. Patient 11 had a brain scan after finding of the ACTA2 p.Arg179 mutation accounting for bladder and lung symptoms (Richer et al., 2012). Patient 12 presented with persistent ductus arteriosus and unreactive pupils; the finding of the ACTA2 p.Arg179 mutation prompted brain scanning though the child was neurologically intact. ...
Article
Mutations in the ACTA2 gene lead to diffuse and diverse vascular diseases; the Arg179His mutation is associated with an early onset severe phenotype due to global smooth muscle dysfunction. Cerebrovascular disease associated with ACTA2 mutations has been likened to moyamoya disease, but appears to have distinctive features. This study involved the analysis of neuroimaging of 13 patients with heterozygous missense mutations in ACTA2 disrupting Arg179. All patients had persistent ductus arteriosus and congenital mydriasis, and variable presentation of pulmonary hypertension, bladder and gastrointestinal problems associated with this mutation. Distinctive cerebrovascular features were dilatation of proximal internal carotid artery, occlusive disease of terminal internal carotid artery, an abnormally straight course of intracranial arteries, and absent basal 'moyamoya' collaterals. Patterns of brain injury supported both large and small vessel disease. Key differences from moyamoya disease were more widespread arteriopathy, the combination of arterial ectasia and stenosis and, importantly, absence of the typical basal 'moyamoya' collaterals. Evaluation of previously published cases suggests some of these features are also seen in the ACTA2 mutations disrupting Arg258. The observation that transition from dilated to normal/stenotic arterial calibre coincides with where the internal carotid artery changes from an elastic to muscular artery supports the hypothesis that abnormal smooth muscle cell proliferation caused by ACTA2 mutations is modulated by arterial wall components. Patients with persistent ductus arteriosus or congenital mydriasis with a label of 'moyamoya' should be re-evaluated to ensure the distinctive neuroimaging features of an ACTA2 mutation have not been overlooked. This diagnosis has prognostic and genetic implications, and mandates surveillance of other organ systems, in particular the aorta, to prevent life-threatening aortic dissection.
... 4,5 Later, variants in ACTA2 were shown to be associated with multisystemic smooth muscle dysfunction syndrome (MIM: 613834) and a broad phenotypic spectrum. 6,7 A group among the visceral myopathies comprises the enteric visceral myopathies characterized predominantly by impaired gastrointestinal propulsion resulting in pain, distention, malabsorption and even death. 8,9 Reports on familial cases have indicated an autosomal dominant inheritance. ...
... Pathogenic variants in ACTA2 are predominantly associated with vascular symptoms including familial thoracic aneurysms, 5 but may in rare cases involve visceral organs including the urinary and gastrointestinal tracts. 6,7 On the other hand, ACTG2 was recently found mutated in a family with FVM and adult gastrointestinal problems, 14 as well as in the MMIH syndrome with severe neonatal symptoms from the intestines and the urinary tract. 15,16 The family investigated in this study shows a phenotypic overlap with both FVM and the MMIH syndrome but our observations on the variable onset as well as the involvement of the bile tract and uterus add to previous reports. ...
Article
Full-text available
Familial visceral myopathy (FVM) is a rare heritable and heterogeneous condition due to impaired smooth muscle function. We identified a family segregating 11 individuals with a spectrum of visceral symptoms involving the small intestine, colon, biliary tract, urinary tract and uterus. Whole-exome sequencing revealed a novel heterozygous tandem base substitution c.806_807delinsAA (p.(Gly269Glu)) in ACTG2, encoding smooth muscle actin γ-2, in affected family members. Variants in ACTG2 were recently identified in FVM with intestinal pseudo-obstruction as well as with the congenital megacystics-microcolon-intestinal hypoperistalsis syndrome. In our family, eight affected members presented with severe complications from the biliary and/or the urinary tracts in addition to gastrointestinal pseudo-obstructions. Furthermore, all affected mothers had a history of assisted deliveries owing to poor progress during labor and weak uterine contractions. The variable involvement of multiple smooth muscle-dependent organs in our family, including the biliary tract and the uterus, add to the phenotypic spectrum associated with ACTG2 missense variants.European Journal of Human Genetics advance online publication, 18 March 2015; doi:10.1038/ejhg.2015.49.
... However, ACTA2 cerebral arteriopathy is now classified as a novel cerebrovascular disease with unique genetic loci, histopathologic findings, and cerebrovascular features. To cerebral arteriopathy have been reported and confirmed via genotyping [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Here, we provide a literature review of ACTA2 cerebral arteriopathy encompassing the history of the disease from first observation to new classification, clinical significance and neurosurgical management strategies. ...
... In 2012, Munot et al. [4] performed a detailed neuroimaging analysis of patients with heterozygous ACTA2 missense mutations. The analyses included 6 new patients (5 with Arg179His and one with Arg179Leu), 5 patients with Arg179His reported by Milewicz et al. [2] and 1 patient with Arg179His reported by Richer et al. [5]. All patients exhibited a similar unique syndrome encompassing cerebrovascular disease, congenital mydriasis, and patent ductus arteriosus [4]. ...
Article
Full-text available
Background: Missense mutations in the gene that codes for smooth muscle actin, ACTA2, cause diffuse smooth muscle dysfunction and a distinct cerebral arteriopathy collectively known as multisystemic smooth muscle dysfunction syndrome (MSMDS). Until recently, ACTA2 cerebral arteriopathy was considered to be a variant of moyamoya disease. However, recent basic science and clinical data have demonstrated that the cerebral arteriopathy caused by mutant ACTA2 exhibits genetic loci, histopathology, neurological sequelae, and radiographic findings unique from moyamoya disease. We conducted a literature review to provide insight into the history, clinical significance, and neurosurgical management of this recently described novel cerebral arteriopathy. Summary: We performed a literature search using PubMed with the key words "ACTA2 mutation," "ACTA2 cerebral arteriopathy," and "multisystemic smooth muscle dysfunction syndrome." Case reports with confirmed ACTA2 mutations and cerebral arteriopathy were included in our review. Our literature search revealed 15 articles (58 cases) of confirmed ACTA2 cerebral arteriopathy. Distinctive features of this arteriopathy included an aberrant internal carotid circulation with dilatation of the proximal segments, occlusive disease at the distal segments, and dolichoectasia. As such, mutant ACTA2 predisposed patients to ischemic strokes as children. Direct and indirect cerebral revascularization procedures are the mainstay treatment options with varying degrees of success. Key Messages: ACTA2 cerebral arteriopathy is a recently described novel cerebrovascular disease seen in patients with MSMDS. Patients currently diagnosed with moyamoya disease who also have dysfunction of smooth muscle organs may benefit from reevaluation by a medical geneticist and ACTA2 genotyping.
... b [Gauthier et al., 2014]. c [Milewicz et al., 2010]; [Al-Mohaissen et al., 2012]; [Moller et al., 2012]; [Munot et al., 2012]; [Richer et al., 2012]; [Meuwissen et al., 2013]; [Moosa et al., 2013]; [Amans et al., 2014]; [Brodsky et al., 2014]; [Roulez et al., 2014]; [Yetman et al., 2015]. d Unknown finding in five of the 23 individuals (18 evaluated patients), 16/18, one individual inherited the variant from the father, who presented with milder disease-family 34 [Wangler et al., 2014] and parental inheritance in a family due to probable gonadal mosacism-family 1 [Tuzovic et al., 2015]. ...
... However, the pupils and their responses to light, and cholinergic agents seem to be different in these disorders. While the pupils in MSMDS are usually nonreactive to the light and the pilocarpine [Moller et al., 2012;Richer et al., 2012;Roulez et al., 2014], the pupils of the individuals with variants in CHRM3 are described as having impaired constriction to light [Weber et al., 2011]. The presence of a weak light reflex and a very little change in pupil size when pilocarpine is instilled in Chrm3 mutant mice support the hypothesis that other mechanisms could be related to the contraction of the pupillary sphincter muscle [Matsui et al., 2000]. ...
Article
Visceral motility dysfunction is a key feature of genetic disorders such as megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS, MIM moved from 249210 to 155310), chronic intestinal pseudo-obstruction (CIPO, MIM609629), and multisystemic smooth muscle dysfunction syndrome (MSMDS, MIM613834). The genetic bases of these conditions recently begun to be clarified with the identification of pathogenic variants in ACTG2, ACTA2, and MYH11 in individuals with visceral motility dysfunction. The MMIHS was associated with the heterozygous variant in ACTG2 and homozygous variant in MYH11, while the heterozygous variant in ACTA2 was observed in patients with MSMDS. In this study, we describe the clinical data as well as the molecular investigation of seven individuals with visceral myopathy phenotypes. Five patients presented with MMIHS, including two siblings from consanguineous parents, one had CIPO, and the other had MSMDS. In three individuals with MMIHS and in one with CIPO we identified heterozygous variant in ACTG2, one being a novel variant (c.584C>T—p.Thr195Ile). In the individual with MSMDS we identified a heterozygous variant in ACTA2. We performed the whole-exome sequencing in one sibling with MMIHS and her parents; however, the pathogenic variant responsible for her phenotype could not be identified. These results reinforce the clinical and genetic heterogeneity of the visceral myopathies. Although many cases of MMIHS are associated with ACTG2 variants, we suggest that other genes, besides MYH11, could cause the MMIHS with autosomal recessive pattern.
... Her overall situation has remained well to date. Tables 1-4 summarizes the systemic features of the reported patients with MSMDS worldwide [8][9][10][11][12][13][14][15][16] . SMCs are widely distributed in the gastrointestinal tract, urinary tract, respiratory tract, uterus, iris, and other body parts. ...
... Our patient had skin and mucosal symptoms, which manifested as cyan-purple plaques on her right face, buccal mucosa, oral tongue, and palate. Richer et al [14] first reported a case of skin abnormalities in which wrinkles of ankles, knees, buttocks, and elbows were markedly deepened. This may be related to the dysfunction of myofibroblasts expressing ACTA2 in the skin. ...
Article
Background: Multisystemic smooth muscle dysfunction syndrome (MSMDS) is a rare genetic disease worldwide. The main mutation is the actin alpha 2 (ACTA2) gene p.R179H. In this paper, we report a Chinese MSMDS patient and systematically review the previous literature. Case summary: Here, we report a 9.6-month-old Chinese girl who was diagnosed with MSMDS based on her history and symptoms, such as recurrent cough, wheezing, and complications with congenital fixed dilated pupils. Chest high-resolution computed tomography revealed inhomogeneous lung transparency, obvious exudative lesions, and some lung fissures that were markedly thickened. Cranial magnetic resonance imaging excluded bleeding and infarction but showed abnormal signals in the centrum ovale majus and bilateral periventricular regions. Echocardiography only showed patent foramen ovale, and no patent ductus arteriosus, pulmonary artery dilatation, or pulmonary hypertension was found. Bronchoscopy indicated moderate bronchial malacia. These examinations in conjunction with the typical eye abnormality suggested a diagnosis of MSMDS, and sequencing of exon 6 of the ACTA2 gene demonstrated the heterozygous mutation c.536G>A, p.R179H. However, her parents' gene analyses were normal. Conclusion: MSMDS is a rare genetic disease mainly caused by the mutation of the ACTA2 gene p.R179H. Early genetic diagnosis should be performed for children presenting with congenital fixed dilated pupils and patent ductus arteriosus. During the process of diagnosis and treatment, clinicians should be on high alert for cerebrovascular, cardiovascular, and pulmonary complications.
... Multisystem smooth muscle dysfunction syndrome (MSMD syndrome, OMIM #613834, ORPHA 404463) is a severe phenotype caused by de novo pathogenic variants affecting the Arg179 residue of the ACTA2 gene and is characterized by aortic and cerebrovascular disease, fixed mydriatic pupils, hypotonic bladder, intestinal hypoperistalsis, pulmonary hypertension and white matter brain anomalies [16][17][18][19][20][21][22][23]. Specific management recommendations have been suggested for MSMD syndrome patients and therefore MSMD is not included in these recommendations [24]. ...
Article
Full-text available
The ACTA2 gene encodes for smooth muscle specific α-actin, a critical component of the contractile apparatus of the vascular smooth muscle cell. Pathogenic variants in the ACTA2 gene are the most frequently encountered genetic cause of non-syndromic hereditary thoracic aortic disease (HTAD). Although thoracic aortic aneurysm and/or dissection is the main clinical manifestation, a variety of occlusive vascular disease and extravascular manifestations occur in ACTA2 -related vasculopathy. Current data suggest possible mutation-specific manifestations of vascular and extra-aortic traits. Despite its relatively high prevalence, comprehensive recommendations on the care of patients and families with pathogenic variants in ACTA2 have not yet been established. We aimed to develop a consensus document to provide medical guidance for health care professionals involved in the diagnosis and treatment of patients and relatives with pathogenic variants in ACTA2 . The HTAD Working Group of the European Reference Network for Rare Vascular Diseases (VASCERN) convened to review current literature and discuss expert opinions on clinical management of ACTA2 related vasculopathy. This consensus statement summarizes our recommendations on diagnosis, monitoring, treatment, pregnancy, genetic counselling and testing in patients with ACTA2- related vasculopathy. However, there is a clear need for additional prospective multicenter studies to further define proper guidelines.
... Seven SMDS cases were initially reported, 1 followed by reports of cases with similar presentation and additional complications often resulting in poor health outcomes and early deaths. [2][3][4][5][6][7][8][9][10][11][12][13] The clinical evolution of the recently identified SMDS has not been described and guidelines for evaluation and medical management are lacking. Therefore, we sought to describe the clinical history and outcomes of SMDS patients. ...
Article
Purpose Smooth muscle dysfunction syndrome (SMDS) due to heterozygous ACTA2 arginine 179 alterations is characterized by patent ductus arteriosus, vasculopathy (aneurysm and occlusive lesions), pulmonary arterial hypertension, and other complications in smooth muscle–dependent organs. We sought to define the clinical history of SMDS to develop recommendations for evaluation and management. Methods Medical records of 33 patients with SMDS (median age 12 years) were abstracted and analyzed. Results All patients had congenital mydriasis and related pupillary abnormalities at birth and presented in infancy with a patent ductus arteriosus or aortopulmonary window. Patients had cerebrovascular disease characterized by small vessel disease (hyperintense periventricular white matter lesions; 95%), intracranial artery stenosis (77%), ischemic strokes (27%), and seizures (18%). Twelve (36%) patients had thoracic aortic aneurysm repair or dissection at median age of 14 years and aortic disease was fully penetrant by the age of 25 years. Three (9%) patients had axillary artery aneurysms complicated by thromboembolic episodes. Nine patients died between the ages of 0.5 and 32 years due to aortic, pulmonary, or stroke complications, or unknown causes. Conclusion Based on these data, recommendations are provided for the surveillance and management of SMDS to help prevent early-onset life-threatening complications.
... This gene encodes the muscarinic receptor mediating smooth muscle contraction induced by the acetylcholinergic pathway. Also a heterozygous missense pathogenic variation of ACTA2 has been reported in Prune-Belly25 . Very recently, causal variants have been observed in the MYOCD gene in patients with congenital megabladder26 . ...
Article
Full-text available
Megacystis‐Microcolon‐Intestinal‐Hypoperistalsis‐syndrome(MMIHS) is a severe congenital visceral myopathy characterized by an abdominal distension due to a large non‐obstructed urinary bladder, a microcolon and intestinal hypo‐ or aperistalsis. Most of the patients described to date carry a sporadic heterozygous variant in ACTG2 . More recently, recessive forms have been reported and mutations in MYH11 , LMOD1, MYLK and MYL9 have been described at the molecular level. In the present report, we describe five patients carrying a recurrent heterozygous variant in ACTG2 . Exome sequencing performed in four families allowed us to identify the genetic cause in three. In two families, we identified variants in MMIHS causal genes, respectively a nonsense homozygous variant in MYH11 and a previously described homozygous deletion in MYL9 . Finally, we identified compound heterozygous variants in a novel candidate gene, PDCL3 , c.[143_144del];[380G > A], p.[(Tyr48Ter)];[(Cys127Tyr)]. After cDNA analysis, a complete absence of PDLC3 expression was observed in affected individuals, indicating that both mutated transcripts were unstable and prone to mediated mRNA decay. PDCL3 encodes a protein involved in the folding of actin, a key step in thin filament formation. Presumably, loss of function of this protein affects the contractility of smooth muscle tissues, making PDCL3 an excellent candidate gene for autosomal recessive forms of MMIHS. This article is protected by copyright. All rights reserved.
... However, vascular smooth muscle disease has also been attributed to mutations in actin and myosin genes with the discovery of mutations in ACTA2 [48] and MYH11 [49] in thoracic aortic aneurysms and dissections. There are also reports of a specific mutation in ACTA2 associated with vascular aneurysms and hypomotility of the gastrointestinal tract (OMIM 613834) [50] and also with prune belly sequence [51]. Additionally, as mentioned above, adult onset visceral myopathy was recently associated with a dominant mutation in the ACTG2 enteric actin gene in a Finnish family [20]. ...
Article
Full-text available
Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disorder of enteric smooth muscle function affecting the intestine and bladder. Patients with this severe phenotype are dependent on total parenteral nutrition and urinary catheterization. The cause of this syndrome has remained a mystery since Berdon's initial description in 1976. No genes have been clearly linked to MMIHS. We used whole-exome sequencing for gene discovery followed by targeted Sanger sequencing in a cohort of patients with MMIHS and intestinal pseudo-obstruction. We identified heterozygous ACTG2 missense variants in 15 unrelated subjects, ten being apparent de novo mutations. Ten unique variants were detected, of which six affected CpG dinucleotides and resulted in missense mutations at arginine residues, perhaps related to biased usage of CpG containing codons within actin genes. We also found some of the same heterozygous mutations that we observed as apparent de novo mutations in MMIHS segregating in families with intestinal pseudo-obstruction, suggesting that ACTG2 is responsible for a spectrum of smooth muscle disease. ACTG2 encodes γ2 enteric actin and is the first gene to be clearly associated with MMIHS, suggesting an important role for contractile proteins in enteric smooth muscle disease.
... The p.Arg179His mutation has been associated with global smooth muscle dysfunction and diverse vasculopathies, including congenital mydriasis, hypotonic bladder, malrotation, gut hypoperistalsis, pulmonary hypertension, patent ductus arteriosus, and central nervous system anomalies. [9][10][11][12] Cerebrovascular occlusive disease is a common complication associated with ACTA2 mutations. Analysis of mutations that have been identified in more than 15 individuals indicate that p.Arg258Cys and p.Arg258His mutations confer a 6.5-fold increased risk of stroke as compared with other mutations, but are not associated with coronary artery disease. ...
Article
Full-text available
Thoracic aortic aneurysm (TAA) is a genetically mediated disease with variable age of onset. In the pediatric age range, nonsyndromic TAA frequently has a milder course than syndromic forms of TAA, such as Marfan syndrome or Loeys-Dietz syndrome. Herein, we describe 17-year-old identical twin brothers with severe progressive TAA due to a novel de novo ACTA2 mutation. Interestingly, both boys were diagnosed at age 11 with congenital mydriasis, a recently recognized manifestation of some ACTA2 mutations due to smooth muscle dysfunction. One of the brothers presented with acute-onset lower back pain that was identified as dissection of an abdominal aortic aneurysm. Imaging of the chest at this time showed severe fusiform TAA. Cardiac imaging in his twin showed similar TAA, but no abdominal aortic aneurysm. Both brothers underwent valve-sparing aortic root replacement, but have had progressive aortic disease with recurrent dissection requiring multiple surgeries. This case emphasizes the importance of identifying physical stigmata of smooth muscle dysfunction, such as mydriasis, as potential markers for associated aortopathy and vascular diseases.
... MMIHS is a rare congenital disease of the visceral organs, mainly characterized by bladder distension and functional intestinal obstruction [8]. Lots of smooth muscle-related genetic mutations were identified to link with MMIHS, such as heterozygous mutations in MYH11 and ACTA2 [9][10][11], and homozygous mutations in smooth muscle gamma-2 actin (ACTG2), MYH11, myosin light chain kinase (MYLK), and leimodin 1(LMOD1) [12][13][14][15][16]. Although the identification of pathogenic variants in these genes explains approximately 90% of all MMIHS, for some affected individuals, the causative mutation and associated gene have yet to be identified. ...
Article
Full-text available
Rationale: Smooth muscle-motility disorders are mainly characterized by impaired contractility and functional intestinal obstruction. Some of these cases are caused by genetic mutations of smooth muscle genes ACTA2, ACTG2, MYH11, MYLK and LMOD1. Still the etiology is complex and multifactorial and the underlying pathology is poorly understood. Integrin interaction protein Kindlin-2 is widely expressed in striated and smooth muscle cells (SMC). However, the function of Kindlin-2 in the smooth muscle remains elusive. Methods: We generated two mouse models using different cre promoter transgenic mice, Kindlin-2fl/fl SM22α-cre+ (cKO mice) and Kindlin-2fl/fl; MYH-cre+ (iKO mice). Embryos and adult tissues were prepared for hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) apoptosis assay. We investigated ultrastructure changes of mouse smooth muscle using transmission electron microscopy (TEM) and measured smooth muscle contractile force in mounting aortic and intestinal rings using the multiwire myograph system (DMT 620M). In addition, cell traction force microscopy (CTFM) was applied to observe the functional change of primary SMC after Kindlin-2 depletion by RNAi. Results: Depletion of Kindlin-2 encoding gene Fermt2 in embryonic smooth muscles leads to apoptosis, downregulates the key components of SMC, impairs smooth muscle development, and finally causes embryonic death at E14.5. Tamoxifen-induced Kindlin-2-specific knockout in adult mouse smooth muscle showed decreased blood pressure, intestinal hypoperistalsis, and eventually died of intestinal obstruction. Kindlin-2 depletion also leads to downregulated Myh11, α-SMA, and CNN, shortened myofilament, broken myofibrils, and impaired contractility of the smooth muscles in iKO mice. Mechanistically, loss of Kindlin-2 decreases Ca2+ influx in primary vascular smooth muscle cells (PVSMC) by downregulating the expression of calcium-binding protein S100A14 and STIM1. Conclusion: We demonstrated that Kindlin-2 is essential for maintaining the normal structure and function of smooth muscles. Loss of Kindlin-2 impairs smooth muscle formation during embryonic development by inducing apoptosis and jeopardizes the contraction of adult smooth muscle by blocking Ca2+ influx that leads to intestinal obstruction. Mice with Kindlin-2 depletion in adult smooth muscle could be a potent animal model of intestinal obstruction for disease research, drug treatment and prognosis.
... The orthologous p.Arg179His mutation in ACTA2 causes severe multisystem smooth muscle cell dysfunction with early-onset vascular disease similar to moyamoya disease [26] . The p.Arg179His mutation in ACTA2 has also been reported in a patient with prune belly sequence and firsttrimester-onset fetal megacystis [27] . The mutation at amino acid 179 in ACTA2 causes a more severe vascular phenotype than the mutation at amino acid 258 [22] . ...
Article
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To identify the molecular basis for prenatally suspected cases of megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) (MIM 249210) in 3 independent families with clinical and radiographic evidence of MMIHS. Whole-exome sequencing (WES) and Sanger sequencing of the ACTG2 gene. We identified a novel heterozygous de novo missense variant in ACTG2 c.770G>A (p.Arg257His) encoding γ-2 smooth muscle actin (ACTG2) in 2 siblings with MMIHS, suggesting gonadal mosaicism of one of the parents. Two additional de novo missense variants (p.Arg257Cys and p.Arg178His) in ACTG2 were identified in 2 additional MMHIS patients. All of our patients had evidence of fetal megacystis and a normal or slightly increased amniotic fluid volume. Additional findings included bilateral renal hydronephrosis, an enlarged fetal stomach, and transient dilated bowel loops. ACTG2 immunostaining of the intestinal tissue showed an altered muscularis propria, a markedly thinned longitudinal muscle layer, and a reduced amount and abnormal distribution of ACTG2. Our study demonstrates that de novo mutations in ACTG2 are a cause of fetal megacystis in MMIHS and that gonadal mosaicism may be present in a subset of cases. These findings have implications for the counseling of families with a diagnosis of fetal megacystis with a preserved amniotic fluid volume and associated gastrointestinal findings. © 2015 S. Karger AG, Basel.
... These were manifested by both acute ischemic change, such as stroke, and chronic ischemic change in the form of leukoencephalopathy and neuronal loss. The MRI T2-weighted hyperintensities in the periventricular white matter (leukoaraiosis) have been previously observed in ACTA2 patients with R179 mutations [10,12,[30][31][32] but the histopathologic basis has not been clearly defined. We found areas of rarefaction containing axonal swellings at these sites, similar to lesions described in hereditary diffuse leukoencephalopathy with axonal spheroids and sometimes also seen in CADASIL [16,33]. ...
Article
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Smooth muscle cell contraction is an essential function of arteries and relies on the integrity of the actin-myosin apparatus. The tissue-specific α2-smooth muscle actin, encoded by ACTA2, is predominantly expressed in vascular smooth muscle cells. ACTA2 mutations predispose to development of aortic aneurysms and early onset coronary and cerebrovascular disease. Based on arteriographic findings, a distinct cerebrovascular disease has been proposed for ACTA2 heterozygous patients carrying the R179H mutation. We present the first integrated analysis of a severely compromised patient with the R179H mutation and define the arterial pathology of ACTA2-related cerebrovascular disease. Histologically, striking morphological abnormalities were present in cerebral arteries of all sizes. Massive intimal smooth muscle cell proliferation, fragmentation of the elastic laminae and medial fibromuscular proliferation characterized large arteries whereas prominent vessel wall thickening, fibrosis and smooth muscle cell proliferation were unique changes in small arteries. The medial fibrosis and smooth muscle cell proliferation explain the characteristic radiologic appearance of “straight arteries” and suggest impaired function of mutant smooth muscle cells. Actin three-dimensional molecular modeling revealed critical positioning of R179 at the interface between the two strands of filamentous actin and destabilization of inter-strand bundling by the R179H mutation, explaining the severe associated phenotype. In conclusion, these characteristic clinical and pathologic findings confirm ACTA2-related cerebrovascular disease as a new cerebrovascular disorder for which new therapeutic strategies need to be designed.
... However, considering that in our cohort, patients with a variant in residue 178 died a few days after birth, and the only patient alive has a R40 variant (S6), it is tempting to speculate that variants affecting residue 178 have a stronger dominant effect leading to a more severe phenotype. Interestingly, residue 178 of ACTG2 corresponds to residue 179 of ACTA2, which has been reported to be mutated in patients diagnosed with early-onset vascular disease associated with smooth muscle cell dysfunction (23), and in a patient with prune belly syndrome (24), supporting a stronger effect of this variant on the overall phenotype. Our MD simulations also corroborate this idea, since the structural changes assessed from visual inspection of the MD trajectories were generally more predominant for the R178 mutants when compared with the others. ...
Article
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Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS) is a rare congenital disorder, in which heterozygous missense variants in the Enteric Smooth Muscle actin γ-2 (ACTG2) gene have been recently identified. To investigate the mechanism by which ACTG2 variants lead to MMIHS, we screened a cohort of eleven MMIHS patients, eight sporadic and three familial cases, and performed immunohistochemistry, molecular modeling and molecular dynamics (MD) simulations, and in vitro assays. In all sporadic cases, a heterozygous missense variant in ACTG2 was identified. ACTG2 expression was detected in all intestinal layers where smooth muscle cells are present in different stages of human development. No histopathological abnormalities were found in the patients. Using molecular modeling and MD simulations, we predicted that ACTG2 variants lead to significant changes to the protein function. This was confirmed by in vitro studies, which showed that the identified variants not only impair ACTG2 polymerization, but also contribute to reduced cell contractility. Taken together, our results confirm the involvement of ACTG2 in sporadic MMIHS, and bring new insights to MMIHS pathogenesis.
... 17 On the other hand, the p.(R179H) variant in ACTA2 causes severe multisystem smooth muscle cell dysfunction with early-onset vascular disease 18 and has also been reported in a patient with prune belly sequence and first trimester-onset fetal megacystis. 19 Interestingly, variants of Arg179 in ACTA2 cause more severe phenotypes than variants of Arg258, 17 thus confirming similar effects of substitutions at paralogous nucleotide positions of ACTA2 and ACTG2 genes and, therefore, the genotype-phenotype correlation we propose for variants at residues Arg257 and Arg178 of the ACTG2 gene. The cases of variants of codons Arg38 and Arg148 need to be also considered. ...
Article
Chronic intestinal pseudo-obstruction (CIPO) syndromes are heterogeneous gastrointestinal disorders, caused by either neuropathy or myopathy, resulting in compromised peristalsis and intestinal obstruction. CIPO can have a profound impact on quality of life, leading the most severely affected individuals to life-long parenteral nutrition and urinary catheterization. To search for disease causing gene(s), we performed the whole exome sequencing (WES) in both eight sporadic and two familial cases, followed by targeted sequencing in additional CIPO patients. After identifying a heterozygous missense variant in the ACTG2 gene in one of 10 patients undergone WES, targeted Sanger sequencing of this gene allowed to detect heterozygous missense variants in 9 of 23 further patients with either megacystis-microcolon-intestinal hypoperistalsis syndrome or intestinal pseudo-obstruction. Variants thus identified, one of which still unreported, affect highly conserved regions of the ACTG2 gene that encodes a protein crucial for correct enteric muscle contraction. These findings provided evidence for a correlation between the clinical phenotype and genotype at the ACTG2 locus, a first step to improve the diagnosis and prognosis of these severe conditions.European Journal of Human Genetics advance online publication, 27 January 2016; doi:10.1038/ejhg.2015.275.
... Besides our case, we searched PubMed for a total of 19 published articles involving 37 MSMDS patients. Details of these cases are summarized in Table 2 [1,2,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. According to the analysis of these patients, the youngest was age 3 d [8] and the oldest 41 years [12]. ...
Article
Background: ACTA2 gene is a specific gene that encodes actin α2. Multisystem smooth muscle dysfunction syndrome (MSMDS) is a multisystem disease characterized by aortic and cerebrovascular lesions caused by ACTA2 gene mutations. There have been many reports of cardiac, pulmonary and cerebrovascular lesions caused by MSMDS; however, few studies have focused on seizures caused by MSMDS. Case summary: Our patient was a girl aged 7 years and 8 mo with recurrent cough, asthma and seizures for 7 years. She was diagnosed with severe pneumonia, congenital heart disease, cardiac insufficiency, and malnutrition in the local hospital. Cardiac ultrasonography revealed congenital heart disease, patent ductus arteriosus (with a diameter of 0.68 cm), left coronary arteriectasis, patent oval foramen (0.12 cm), tricuspid and pulmonary regurgitation, and pulmonary hypertension. Cerebral magnetic resonance imaging and magnetic resonance angiography indicated stiffness in the brain vessels, together with multiple aberrant signaling shadows in bilateral paraventricular regions. A heterozygous mutation (c.536G>A) was identified in the ACTA2 gene, resulting in generation of p.R179H. Finally, the girl was diagnosed with MSMDS combined with epilepsy. The patient had 4 episodes of seizures before treatment, and no onset of seizure was reported after oral administration of sodium valproate for 1 year. Conclusion: MSMDS has a variety of clinical manifestations and unique cranial imaging features. Cerebrovascular injury and white matter injury may lead to seizures. Gene detection can confirm the diagnosis and prevent missed diagnosis or misdiagnosis.
... 5,6,14 Also in the neuro-muscular category is CHRM3 that encodes M3, the key acetylcholine receptor expressed by detrusor smooth muscle cells that is required for parasympathetic-driven detrusor contraction and bladder emptying. 2 In this report, we present a second family carrying a homozygous variant in CHRM3 associated with familial urinary bladder disease. ...
Article
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CHRM3 codes for the M3 muscarinic acetylcholine receptor that is located on the surface of smooth muscle cells of the detrusor, the muscle that effects urinary voiding. Previously, we reported brothers in a family affected by a congenital prune belly‐like syndrome with mydriasis due to homozygous CHRM3 frameshift variants. In this study we describe two sisters with bladders that failed to empty completely and pupils that failed to constrict fully in response to light, who are homozygous for the missense CHRM3 variant c.352G>A; p.(Gly118Arg).,. Samples were not available for genotyping from their brother, who had a history of multiple urinary tract infections and underwent surgical bladder draining in the first year of life. He died at six years. This is the first independent report of biallelic variants in CHRM3 in a family with a rare serious bladder disorder associated with mydriasis and provides important evidence of this association. This article is protected by copyright. All rights reserved.
... These extra-GU features (particularly those that appear syndromic) provide salient targets for genetic investigation, even for pseudo-prunes, as they may represent a milder expression of causal mutations vs other syndromes with overlapping pathogenesis. Furthermore, DNA variations in four autosomal genes [cholinergic receptor muscarinic 3 (CHRM3); hepatocyte nuclear factor 1b (HNF1b); actin, a 2 , smooth muscle, aorta (ACTA2); and actin, c 2 , smooth muscle, enteric (ACTG2)] have been associated with five sporadic PBS cases [12,37,42] and one PBS multiplex consanguineous kindred [13]. DNA variants in these autosomal genes would manifest theoretically in females at near equal frequency as in males. ...
Article
Objective To design a novel system of scoring Prune Belly Syndrome (PBS) phenotypic severity at any presenting age and apply it to a large pilot cohort. Patients And Methods From 2000‐2017, PBS patients were recruited to our prospective PBS study and medical records were cross‐sectionally analyzed, generating individualized RUBACE scores. We designed the pragmatic RUBACE scoring system based on six sub‐scores (R: renal, U: ureter, B: bladder/outlet, A: abdominal wall, C: cryptorchidism, E: extra‐genitourinary, generating the acronym RUBACE), yielding a potential summed score of 0‐31. The E score was utilized to segregate syndromic PBS and PBS‐plus variants. The cohort was scored per classic Woodard criteria and RUBACE scores compared to Woodard category. Results 48 males and two females had mean RUBACE scores of 13.8 (range: 8‐25) at a mean age of 7.3 years. Segregated by phenotypic categories, there were 39 isolated PBS (76%), 6 syndromic PBS (12%) and 5 PBS‐plus (10%) cases. Mean RUBACE scores for Woodard categories 1, 2 and 3 were 20.5 (n=8), 13.8 (n=25), and 10.6 (n=17), respectively (p<0.001). Conclusions RUBACE is a practical, organ/system level, phenotyping tool designed to grade PBS severity and categorize patients into isolated PBS, syndromic PBS, and PBS‐plus groups. This standardized system will facilitate genotype‐phenotype correlations and future prospective multicenter studies assessing medical and surgical treatment outcomes. This article is protected by copyright. All rights reserved.
... Lastly, there have been 12 published multiplex pedigrees without causal genes identified in most [19][20][21][23][24][25][26][27][28][29][30][31]. More recently, five autosomal genes, including CHRM3, HNF1β, ACTA2, ACTG2 and STIM1, have been reported with potentially causal DNA variants, including structural, copy number, and single nucleotide variants, however these genes each only account for one or two PBS cases or one PBS multiplex consanguineous kindred [32][33][34][35][36][37][38]. Moreover, none of the currently suggested candidate genes fit an X-linked recessive mode of inheritance and functional data is lacking for many of these candidate genetic variants. ...
Article
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Background: Prune belly syndrome (PBS) is a rare, multi-system congenital myopathy primarily affecting males that is poorly described genetically. Phenotypically, its morbidity spans from mild to lethal, however, all isolated PBS cases manifest three cardinal pathological features: 1) wrinkled flaccid ventral abdominal wall with skeletal muscle deficiency, 2) urinary tract dilation with poorly contractile smooth muscle, and 3) intra-abdominal undescended testes. Despite evidence for a genetic basis, previously reported PBS autosomal candidate genes only account for one consanguineous family and single cases. Methods: We performed whole exome sequencing (WES) of two maternal adult half-brothers with syndromic PBS (PBS + Otopalatodigital spectrum disorder [OPDSD]) and two unrelated sporadic individuals with isolated PBS and further functionally validated the identified mutations. Results: We identified three unreported hemizygous missense point mutations in the X-chromosome gene Filamin A (FLNA) (c.4952 C > T (p.A1448V), c.6727C > T (p.C2160R), c.5966 G > A (p.G2236E)) in two related cases and two unrelated sporadic individuals. Two of the three PBS mutations map to the highly regulatory, stretch-sensing Ig19-21 region of FLNA and enhance binding to intracellular tails of the transmembrane receptor β-integrin 1 (ITGβ1). Conclusions: FLNA is a regulatory actin-crosslinking protein that functions in smooth muscle cells as a mechanosensing molecular scaffold, transmitting force signals from the actin-myosin motor units and cytoskeleton via binding partners to the extracellular matrix. This is the first evidence for an X-linked cause of PBS in multiple unrelated individuals and expands the phenotypic spectrum associated with FLNA in males surviving even into adulthood.
Article
We describe a neonatal patient with fixed dilated pupils and pulmonary, bladder, and bowel dysfunction suspicious for the presence of ACTA2 R179 mediated multisystemic smooth muscle dysfunction syndrome. Whole exome sequencing revealed compound heterozygous mutations in MYH11 after ACTA2 specific testing revealed no abnormalities. The child lived until 18 months of age and represents the only reported case of an MYH11 compound heterozygote with widespread smooth muscle dysfunction.
Article
-ACTA2 mutations are the major cause of familial thoracic aortic aneurysms and dissections. We sought to characterize these aortic diseases in a large case series of individuals with ACTA2 mutations. -Aortic disease, management, and outcome associated with the first aortic event (aortic dissection or aneurysm repair) were abstracted from the medical records of 277 individuals with 41 various ACTA2 mutations. Aortic events occurred in 48% of these individuals, with the vast majority presenting with thoracic aortic dissections (88%) associated with 25% mortality. Type A dissections were more common than type B dissections (54% versus 21%), but the median age of onset of type B dissections was significantly younger than type A dissections (27 years, IQR 18-41 versus 36 years, IQR 26-45). Only 12% of aortic events were repair of ascending aortic aneurysms, which variably involved the aortic root, ascending aorta and aortic arch. Overall cumulative risk of an aortic event at age 85 years was 0.76 (95% CI 0.64, 0.86). After adjustment for intra-familial correlation, gender and race, mutations disrupting p.R179 and p.R258 were associated with significantly increased risk for aortic events, whereas p.R185Q and p.R118Q mutations showed significantly lower risk of aortic events compared to other mutations. -ACTA2 mutations are associated with high risk of presentation with an acute aortic dissection. The lifetime risk for an aortic event is only 76%, suggesting that additional environmental or genetic factors play a role in expression of aortic disease in individuals with ACTA2 mutations.
Article
Mutations in the smooth muscle-specific isoform of α-actin (ACTA2) cause vascular smooth muscle dysfunction leading to aortic aneurysm and moyamoya syndrome. A unique R179H mutation in ACTA2 has been reported to result in widespread smooth muscle dysfunction affecting vascular and extravascular smooth muscles. We report a 7-year-old girl with an ACTA2 R179H mutation manifesting with neonatal seizures due to multifocal infarcts, asymmetric motor deficits, global developmental delay, spasticity, congenital bilateral mydriasis, and a large patent ductus arteriosus. Serial magnetic resonance imaging (MRI) of the brain over 7 years showed diffuse supratentorial white matter abnormalities consistent with a progressive leukoencephalopathy. Magnetic resonance angiography of the cerebral vessels showed stenosis in the terminal portion of the bilateral internal carotid arteries with fusiform dilation of the proximal segment. Neonatal onset of neurologic symptoms in ACTA2 mutations has not been previously reported. R179H mutation in ACTA2 represents the severe end of the disease spectrum.
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Congenital anomalies of the lower urinary tract (CALUT) are a family of birth defects of the ureter, the bladder, and the urethra. CALUT includes ureteral anomaliesc such as congenital abnormalities of the ureteropelvic junction (UPJ) and ureterovesical junction (UVJ), and birth defects of the bladder and the urethra such as bladder-exstrophy-epispadias complex (BEEC), prune belly syndrome (PBS), and posterior urethral valves (PUVs). CALUT is one of the most common birth defects and is often associated with antenatal hydronephrosis, vesicoureteral reflux (VUR), urinary tract obstruction, urinary tract infections (UTI), chronic kidney disease, and renal failure in children. Here, we discuss the current genetic and molecular knowledge about lower urinary tract development and genetic basis of CALUT in both human and mouse models. We provide an overview of the developmental processes leading to the formation of the ureter, the bladder, and the urethra, and different genes and signaling pathways controlling these developmental processes. Human genetic disorders that affect the ureter, the bladder and the urethra and associated gene mutations are also presented. As we are entering the postgenomic era of personalized medicine, information in this article may provide useful interpretation for the genetic and genomic test results collected from patients with lower urinary tract birth defects. With evidence-based interpretations, clinicians may provide more effective personalized therapies to patients and genetic counseling for their families. WIREs Syst Biol Med 2013. doi: 10.1002/wsbm.1212 For further resources related to this article, please visit the WIREs website.
Article
Lower urinary tract and/or kidney malformations are collectively the most common cause of end-stage renal disease in children, and they are also likely to account for a major subset of young adults requiring renal replacement therapy. Advances have been made regarding the discovery of the genetic causes of human kidney malformations. Indeed, testing for mutations of key nephrogenesis genes is now feasible for patients seen in nephrology clinics. Unfortunately, less is known about defined genetic bases of human lower urinary tract anomalies. The focus of this review is the genetic bases of congenital structural and functional disorders of the urinary bladder. Three are highlighted. First, prune belly syndrome, where mutations of CHRM3, encoding an acetylcholine receptor, HNF1B, encoding a transcription factor, and ACTA2, encoding a cytoskeletal protein, have been reported. Second, the urofacial syndrome, where mutations of LRIG2 and HPSE2, encoding proteins localised in nerves invading the fetal bladder, have been defined. Finally, we review emerging evidence that bladder exstrophy may have genetic bases, including variants in the TP63 promoter. These genetic discoveries provide a new perspective on a group of otherwise poorly understood diseases.
Article
Thoracic aortic aneurysm and dissection (TAAD) are associated with connective tissue disorders like Marfan syndrome and Loeys-Dietz syndrome, caused by mutations in the fibrillin-1, the TGFβ-receptor 1- and -2 genes, the SMAD3 and TGFβ2 genes, but have also been ascribed to ACTA2 gene mutations in adults, spread throughout the gene. We report on a novel de novo c.535C > T in exon 6 leading to p.R179C aminoacid substitution in ACTA2 in a toddler girl with primary pulmonary hypertension, persistent ductus arteriosus, extensive cerebral white matter lesions, fixed dilated pupils, intestinal malrotation, and hypotonic bladder. Recently, de novo ACTA2 R179H substitutions have been associated with a similar phenotype and additional cerebral developmental defects including underdeveloped corpus callosum and vermis hypoplasia in a single patient. The patient here shows previously undescribed abnormal lobulation of the frontal lobes and position of the gyrus cinguli and rostral dysplasis of the corpus callosum; she died at the age of 3 years during surgery due to vascular fragility and rupture of the ductus arteriosus. Altogether these observations support a role of ACTA2 in brain development, especially related to the arginine at position 179. Although all previously reported patients with R179H substitution successfully underwent the same surgery at younger ages, the severe outcome of our patient warns against the devastating effects of the R179C substitution on vasculature. © 2013 Wiley Periodicals, Inc.
Article
Disease of the wall of the thoracic aorta has many causes: inflammation, infection and atherosclerosis are the most common 'acquired' causes, but even these have genetic predispositions. This article deals with aortic disease due to mutations in specific genes. The conditions can affect tissues and organs other than the aorta (syndromic) or be limited to the aorta (nonsyndromic). A classification scheme based on the gene is emerging, those that affect primarily the extracellular matrix (e.g., FBN1, COL3A1), TGF-β signaling (e.g., TGFBR1, TGFB2), or vascular smooth muscle cell contractility (e.g., ACTA2, MYH11). Understanding pathogenesis is driving the development of novel therapies, such as angiotensin receptor blockade, which is in clinical trial. However, recurrent imaging, restriction of exercise, β-adrenergic blockade, and prophylactic surgery remain effective in preventing dissection and sudden death.
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: Congenital fixed dilated pupils (congenital mydriasis) is characterized by hypoplasia or aplasia of the iris muscles, with absence of iris between the collarette and pupillary border, creating a scalloped pupillary margin. This condition has been reported in a multisystemic smooth muscle cell dysfunction syndrome, combined with congenital patent ductus arteriosus, cerebrovascular disease (Moya-moya-like), coronary artery disease, thoracic aorta aneurysm, and dysfunction of smooth muscle cells in organs throughout the body. All affected individuals carry a p.R179H heterozygous mutation in the ACTA2 gene. We add to the ophthalmologic involvement with 3 more patients. Congenital fixed dilated pupils is a rare condition and should alert ophthalmologists to the possibility of the coexistence of systemic life-threatening disorders.
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The urinary tract comprises the renal pelvis, the ureter, the urinary bladder, and the urethra. The tract acts as a functional unit, first propelling urine from the kidney to the bladder, then storing it at low pressure inside the bladder which intermittently and completely voids urine through the urethra. Congenital diseases of these structures can lead to a range of diseases sometimes associated with fetal losses or kidney failure in childhood and later in life. In some of these disorders, parts of the urinary tract are severely malformed. In other cases, the organs appear grossly intact yet they have functional deficits that compromise health. Human studies are beginning to indicate monogenic causes for some of these diseases. Here, the implicated genes can encode smooth muscle, neural or urothelial molecules, or transcription factors that regulate their expression. Furthermore, certain animal models are informative about how such molecules control the development and functional differentiation of the urinary tract. In future, novel therapies, including those based on gene transfer and stem cell technologies, may be used to treat these diseases to complement conventional pharmacological and surgical clinical therapies.
Article
We report the association of congenital mydriasis with prune belly syndrome and cerebrovascular anomalies in a 9-year-old boy who was found to have an ACTA2 mutation. This case illustrates the spectrum of systemic malformations that are attributable to mutations in ACTA2 and expands the spectrum of cerebrovascular anomalies that are now known to accompany congenital mydriasis.
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Mutations in leucine-rich-repeats and immunoglobulin-like-domains 2 (LRIG2) or in heparanase 2 (HPSE2) cause urofacial syndrome, a devastating autosomal recessive disease of functional bladder outlet obstruction. It has been speculated that urofacial syndrome has a neural basis, but it is unknown whether defects in urinary bladder innervation are present. We hypothesized that urofacial syndrome features a peripheral neuropathy of the bladder. Mice with homozygous targeted Lrig2 mutations had urinary defects resembling those found in urofacial syndrome. There was no anatomical blockage of the outflow tract, consistent with a functional bladder outlet obstruction. Transcriptome analysis revealed differential expression of 12 known transcripts in addition to Lrig2, including 8 with established roles in neurobiology. Mice with homozygous mutations in either Lrig2 or Hpse2 had increased nerve density within the body of the urinary bladder and decreased nerve density around the urinary outflow tract. In a sample of 155 children with chronic kidney disease and urinary symptoms, we discovered novel homozygous missense LRIG2 variants that were predicted to be pathogenic in 2 individuals with non-syndromic bladder outlet obstruction. These observations provide evidence that a peripheral neuropathy is central to the pathobiology of functional bladder outlet obstruction in urofacial syndrome, and emphasize the importance of LRIG2 and heparanase 2 for nerve patterning in the urinary tract.
Article
Urofacial syndrome (UFS) is characterised by congenital bladder dysfunction accompanied by a characteristic abnormal grimace upon smiling and crying. In recent years, biallelic mutations of HPSE2 and LRIG2 have been reported in UFS patients. Non-neurogenic neurogenic bladder (NNNB) has a bladder identical to UFS without typical facial features. The aim of this study was to analyse HPSE2 mutations in patients with UFS and NNNB or severe lower urinary tract dysfunction (LUTD) without abnormal facial expression. Patients with UFS, NNNB and severe LUTD were enrolled in the study. We examined a total of 35 patients from 33 families. There were seven UFS patients from five different families, 21 patients with NNNB and seven with LUTD. HPSE2 gene mutation analysis was performed using the polymerase chain reaction protocol followed by Sanger sequencing in these patients. A twin pair with UFS was found to be homozygous for c.457C>T (p.Arg153*) mutation. No other pathogenetic variant was detected. HPSE2 mutations were found in one UFS family but not detected in patients with NNNB and severe LUTD. Considering the increasingly recognised cases of NNNB that were diagnosed in early childhood period, genetic factors appear to be responsible. Thus, further genetic studies are needed to discover novel associated gene variants in these bladder anomalies. © 2015 S. Karger AG, Basel.
Article
Congenital bladder neck obstruction (or lower urinary tract obstruction [LUTO]) describes a heterogeneous group of congenital anomalies presenting with similar prenatal ultrasonographic findings of dilated posterior urethra, megacystis, hydronephrosis, oligohydramnios and often with associated renal dysplasia. Untreated LUTO has high rate of perinatal morbidity and mortality from associated pulmonary hypoplasia and early-onset renal failure in infancy. Ultrasonographic features and prospective fetal urinalysis may help in predicting the overall prognosis of congenital LUTO. Currently, fetal vesicoamniotic shunt (of various designs), and fetal cystoscopy and fulguration of the obstruction are potential prenatal interventions. Retrospective and prospective cohort studies and a relatively small randomized controlled trial have demonstrated these treatments may possibly improve perinatal survival. Despite this, concerns remain as to the high rates of renal impairment observed in paediatric survivors. A clinical prospective scoring/staging system may improve prenatal diagnostic criteria and case selection for fetal therapy.
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Cambridge Core - Obstetrics and Gynecology, Reproductive Medicine - High-Risk Pregnancy - edited by David James
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Leucine-rich-repeats and immunoglobulin-like-domains 2 (LRIG2) or heparanase 2 (HPSE2) mutations occur in urofacial, or Ochoa, syndrome (UFS), a devastating autosomal recessive disease of functional bladder outlet obstruction. It has been speculated that UFS has a neural basis but there is no available data regarding whether defects in urinary bladder innervation are present in UFS. We hypothesized that UFS features a peripheral neuropathy of the bladder and therefore studied Lrig2 and Hpse2 mutant mouse bladders. Mice with homozygous targeted Lrig2 mutations had urination defects resembling those found in UFS. These were not caused by anatomical blockage of the outflow tract, supporting the presence of functional bladder outflow obstruction. We showed that mice homozygous for either Lrig2 or Hpse2 mutations have increased nerve density within the body and decreased density around the outflow tract of the urinary bladder. Further emphasizing the role for Lrig2 in bladder biology, we discovered homozygous missense LRIG2 likely pathogenic variants in people with non-syndromic bladder outlet obstruction. These observations provide evidence that a peripheral neuropathy is central to the pathobiology of UFS bladder disease, and emphasize the importance of Lrig2 and heparanase 2 in the urinary tract.
Article
Mutations in the gene ACTA2 are a recognized cause of aortic aneurysms with aortic dissection in adulthood. Recently, a specific mutation (Arg179His) in this gene has been associated with multisystem smooth muscle dysfunction presenting in childhood. We describe 3 patients with an R179H mutation, all of whom presented with an aneurysmal patent ductus arteriosus. Detailed information on the rate of aortic disease progression throughout childhood is provided. Death or need for ascending aortic replacement occurred in all patients. Genetic testing for ACTA2 mutations should be considered in all infants presenting with ductal aneurysms. Copyright © 2015 by the American Academy of Pediatrics.
Article
Prune Belly Syndrome (PBS) is a congenital multisystem myopathy with mild to lethal severity. While of uncertain etiology, 95% male predominance and familial occurrence suggest a genetic basis. As copy number variations (CNVs) can cause unexplained genetic disorders, we tested for novel CNVs in a large PBS population. We genotyped 21 unrelated PBS patients by high-resolution array comparative genomic hybridization (aCGH) and phenotyped using a novel PBS severity scoring system. Available parents were screened for detected CNV via quantitative PCR (qPCR). We additionally screened for recurrence of identified novel candidate CNVs on 106 PBS probands by qPCR. We identified 10 CNVs in 8 of 21 PBS patients tested (38%). Testing confirmed inheritance from an unaffected biological parent in six patients; parental samples were unavailable in two probands. One candidate CNV includes duplication of the X-chromosome AGTR2 gene, known to function in urinary tract development. Subsequent screening of the larger PBS cohort did not identify any recurrent CNVs. Presence of CNV did not correlate with PBS severity scoring. CNVs were uncommon in this large PBS population, but analysis of identified variants may inform disease pathogenesis and reveal targets for therapeutic intervention for this rare, severe disorder.
Article
Thoracic aortic aneurysm is a potentially life-threatening condition in that it places patients at risk for aortic dissection or rupture. However, our modern understanding of the pathogenesis of thoracic aortic aneurysm is quite limited. A genetic predisposition to thoracic aortic aneurysm has been established, and gene discovery in affected families has identified several major categories of gene alterations. The first involves mutations in genes encoding various components of the transforming growth factor beta (TGF-β) signaling cascade (FBN1, TGFBR1, TGFBR2, TGFB2, TGFB3, SMAD2, SMAD3 and SKI), and these conditions are known collectively as the TGF-β vasculopathies. The second set of genes encode components of the smooth muscle contractile apparatus (ACTA2, MYH11, MYLK, and PRKG1), a group called the smooth muscle contraction vasculopathies. Mechanistic hypotheses based on these discoveries have shaped rational therapies, some of which are under clinical evaluation. This review discusses published data on genes involved in thoracic aortic aneurysm and attempts to explain divergent hypotheses of aneurysm origin.
Chapter
A number of complex ocular motility disorders are discussed in this chapter. The diversity of these conditions reflects the need for the ophthalmologist to maintain a broad working knowledge of pediatric neurologic disorders along with their ocular motor manifestations. Some clinical features of these conditions (e.g., congenital ocular motor apraxia, congenital fibrosis syndrome) are sufficiently unique that the diagnosis can be established solely on the basis of the clinical appearance. Other disorders either show overlapping manifestations or effectively masquerade as other entities. Unique features of some conditions, such as conjugate ocular torsion in patients with skew deviation, are considered worthy of emphasis because they significantly expand the differential diagnosis. Indeed, assessment of objective torsion (and subjective torsion when possible) is a necessary component of any comprehensive strabismological evaluation [422]. Correction of coexisting torsion can be integrated into the surgical plan, except when the torsion serves a compensatory function, as in patients with skew deviation.
Article
Visceral smooth muscle is a crucial component of the walls of hollow organs like the gut, bladder, and uterus. This specialized smooth muscle has unique properties that distinguish it from other muscle types and that facilitate robust dilation and contraction. Visceral myopathies are diseases where severe visceral smooth muscle dysfunction prevents efficient movement of air and nutrients though the bowel, impairs bladder emptying, and affects normal uterine contraction and relaxation, particularly during pregnancy. Disease severity exists along a spectrum. The most debilitating defects cause highly dysfunctional bowel, reduced intrauterine colon growth (microcolon), and bladder emptying defects requiring catheterization, a condition called Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS). People with MMIHS often die early in childhood. When the bowel is the main organ affected and microcolon is absent, the condition is known as myopathic chronic intestinal pseudo-obstruction (CIPO). Visceral myopathies like MMIHS and myopathic CIPO are most commonly caused by mutations in contractile apparatus cytoskeletal proteins. Here, we review visceral myopathy-causing mutations and normal functions of these disease-associated proteins. We propose molecular, cellular, and tissue-level models that may explain clinical and histopathological features of visceral myopathy and hope these observations prompt new mechanistic studies.
Article
De novo heterozygous mutations changing R179 to histidine, leucine, or cysteine in the ACTA2 gene are associated with Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS). Characteristic hallmarks of this condition, caused only by these specific ACTA2 mutations, are congenital mydriasis (mid-dilated, non-reactive pupils), a large persistent ductus arteriosus (PDA), aortic aneurysms evolving during childhood, and cerebrovascular anomalies. We describe two patients, a 3-day-old newborn and a 26-year-old woman, with this unique mutation in association with a huge PDA and an aorto-pulmonary window. In addition, one showed a coarctation of the aortic arch and the other a complete interruption of the aortic arch type A; thereby expanding the spectrum of cardiac congenital heart defect of this syndrome. Each patient displayed a huge PDA and an extra-cardiovascular phenotype consistent with MSMDS. These observations exemplify that a functional alpha 2 smooth muscle actin is necessary for proper cardiovascular organ development, and demonstrate that a very exceptional congenital heart defect (aortopulmonary window) can be caused by a mutation in a gene encoding a contractile protein of vascular smooth muscle cells.
Article
Objectives: The diagnosis of chronic intestinal pseudo-obstruction (CIPO) has depended on clinical features, manometry, and imaging. This report aimed to determine the efficacy of sequencing the ACTG2 gene for diagnosis. In addition, the goal was to determine how often a mutation would be found in our randomly collected cohort of probands and those probands published previously. Methods: Whole exome sequencing was performed in 4 probands with CIPO. Subsequently, only the ACTG2 gene was sequenced in another 24 probands (total 28). We analyzed published data of 83 probands plus our 28 [total 111] and determined how many had pathogenic variants and the precise genotype. Results: Whole exome and Sanger sequencing revealed a pathogenic variant in the ACTG2 gene in 4/28 of our probands and in 45 out of 83 published probands [49/111(44.1%)]. Moreover, a mutational hotspot in the ACTG2 gene was recognized. Genetic heterogeneity is evident. Conclusion: Pooled gene sequencing results from one individual in each of 111 families enabled a precise diagnosis of an ACTG2 mutation in 49 (44%). The benefit to patients and families of early confirmation of a motility disorder not only helps avoid unnecessary intervention, but also enables institution of appropriate treatments and avoidance of secondary disorders such as malnutrition and poor growth. Knowledge of a pathogenic variant in a parent, with a 50% risk of recurrence, provides an opportunity for genetic counseling.
Chapter
In 1895, Parker described the congenital triad of deficient abdominal musculature, cryptorchidism, and urinary tract abnormalities. Subsequently, the term “prune belly syndrome” was coined for this condition based on the characteristic wrinkled appearance of the abdomen. The incidence of the syndrome is estimated to be 1 in 35,000 to 1 in 50,000 live births.
Chapter
In 1895, Parker described the congenital triad of deficient abdominal musculature, cryptorchidism, and urinary tract abnormalities. Subsequently, the term “prune belly syndrome” was coined for this condition based on the characteristic wrinkled appearance of the abdomen. The incidence of the syndrome is estimated to be 1 in 35,000 to 1 in 50,000 live births.
Article
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The major function of vascular smooth muscle cells (SMCs) is contraction to regulate blood pressure and flow. SMC contractile force requires cyclic interactions between SMC alpha-actin (encoded by ACTA2) and the beta-myosin heavy chain (encoded by MYH11). Here we show that missense mutations in ACTA2 are responsible for 14% of inherited ascending thoracic aortic aneurysms and dissections (TAAD). Structural analyses and immunofluorescence of actin filaments in SMCs derived from individuals heterozygous for ACTA2 mutations illustrate that these mutations interfere with actin filament assembly and are predicted to decrease SMC contraction. Aortic tissues from affected individuals showed aortic medial degeneration, focal areas of medial SMC hyperplasia and disarray, and stenotic arteries in the vasa vasorum due to medial SMC proliferation. These data, along with the previously reported MYH11 mutations causing familial TAAD, indicate the importance of SMC contraction in maintaining the structural integrity of the ascending aorta.
Article
The purpose of our retrospective observational series was to determine whether the sonographic characteristics of fetal megacystic bladders can be used to reliably establish the most likely diagnosis in fetuses with this condition. The sonographic records of pregnant patients referred to our institutions over a 10-year period who were found on initial 2-dimensional sonography to be carrying fetuses with megacystis were examined for evidence of a keyhole sign, bladder thickness, amniotic fluid index, and fetal sex. When available, 3-/4-dimensional sonography, Doppler angiography, tomographic ultrasound imaging, virtual organ computer-aided analysis, and automatic volume calculation were used as part of the detailed fetal anatomic survey. Twenty fetuses with megacystis were identified. Seventeen were male; 2 were female; and 1 had ambiguous genitalia. All male fetuses with megacystis originally had a diagnosis of prune belly syndrome. The diagnosis for 10 male fetuses with a keyhole sign was changed to megacystis secondary to posterior urethral valves. The fetus with ambiguous genitalia had prune belly syndrome. One of the female fetuses had a diagnosis of urethral atresia, and the diagnosis for the other female fetus was megacystis-microcolon-intestinal hypoperistalsis syndrome. In conclusion, in fetuses with megacystic bladders, it is possible to distinguish between cases with prune belly syndrome, posterior urethral valves, urethral atresia, and megacystis-microcolon-intestinal hypoperistalsis syndrome by a detailed anatomic survey using 2- and 3-/4-dimensioinal sonographic techniques.
Article
The discovery of common genetic patterns in different system vascular diseases may provide important insights into the pathogenesis of these severe medical conditions. Recently, the coincidence of mutations in ACTA2 (vascular smooth muscle cell specific isoform of α-actin) in families with thoracic aortic aneurysms and dissections (TAAD) and Moyamoya disease (MMD) was reported in patients of Northern European descent and a positive family history for TAAD and MMD. In this study, we analyzed the nine exons of the ACTA2 gene in central European patients with non-familial MMD, aiming to replicate previously described genetic findings and possibly identify further mutations. DNA sequencing of the nine exons and flanking intronic regions of ACTA2 was performed in 39 MMD patients with no family history for MMD or TAAD and 68 healthy controls of central European descent with custom made primers. One new mutation (R179H, heterozygous) in exon 6 of ACTA2 was found in one patient with MMD. We were not able to detect other previously described mutations. In contrast to a previous report, we did not identify significant sequence variations in ACTA2. Further combined analysis of ACTA2 and other, possibly causative, genes in larger cohorts of MMD and other vascular diseases may identify possible common disease-causing mechanisms.
Article
Smooth muscle cells (SMCs) contract to perform many physiological functions, including regulation of blood flow and pressure in arteries, contraction of the pupils, peristalsis of the gut, and voiding of the bladder. SMC lineage in these organs is characterized by cellular expression of the SMC isoform of α-actin, encoded by the ACTA2 gene. We report here on a unique and de novo mutation in ACTA2, R179H, that causes a syndrome characterized by dysfunction of SMCs throughout the body, leading to aortic and cerebrovascular disease, fixed dilated pupils, hypotonic bladder, malrotation, and hypoperistalsis of the gut and pulmonary hypertension.
Article
Genetic predisposition to early onset of occlusive vascular diseases, including coronary artery disease, ischemic stroke, and Moyamoya disease, may represent varying presentations of a common underlying dysregulation of vascular smooth muscle cell proliferation. We discuss mutations in two genes, NF1 and ACTA2, which predispose affected individuals to diffuse and diverse vascular diseases. These patients show evidence of diffuse occlusive disease in multiple arterial beds or even develop seemingly diverse arterial pathologies, ranging from occlusions to arterial aneurysms. We also present the current evidence that both NF1 and ACTA2 mutations promote increased smooth muscle cell proliferation in vitro and in vivo, which leads us to propose that these diffuse and diverse vascular diseases are the outward signs of a more fundamental disease: a hyperplastic vasculomyopathy. We suggest that the concept of a hyperplastic vasculomyopathy offers a new approach not only to identifying mutated genes that lead to vascular diseases but also to counseling and possibly treating patients harboring such mutations. In other words, this framework may offer the opportunity to therapeutically target the inappropriate smooth muscle cell behavior that predisposes to a variety of vascular diseases throughout the arterial system.
Article
The vascular smooth muscle cell (SMC)-specific isoform of alpha-actin (ACTA2) is a major component of the contractile apparatus in SMCs located throughout the arterial system. Heterozygous ACTA2 mutations cause familial thoracic aortic aneurysms and dissections (TAAD), but only half of mutation carriers have aortic disease. Linkage analysis and association studies of individuals in 20 families with ACTA2 mutations indicate that mutation carriers can have a diversity of vascular diseases, including premature onset of coronary artery disease (CAD) and premature ischemic strokes (including Moyamoya disease [MMD]), as well as previously defined TAAD. Sequencing of DNA from patients with nonfamilial TAAD and from premature-onset CAD patients independently identified ACTA2 mutations in these patients and premature onset strokes in family members with ACTA2 mutations. Vascular pathology and analysis of explanted SMCs and myofibroblasts from patients harboring ACTA2 suggested that increased proliferation of SMCs contributed to occlusive diseases. These results indicate that heterozygous ACTA2 mutations predispose patients to a variety of diffuse and diverse vascular diseases, including TAAD, premature CAD, ischemic strokes, and MMD. These data demonstrate that diffuse vascular diseases resulting from either occluded or enlarged arteries can be caused by mutations in a single gene and have direct implications for clinical management and research on familial vascular diseases.
Article
Prune belly is a lax, wrinkled abdominal wall and frequently is associated with other anomalies. The prune belly syndrome is a specific constellation of anomalies consisting of an abdominal wall deficient in muscular tissue, dilated urinary tract, and bilateral cryptorchidism. This group of anomalies is also called the Eagle-Barrett syndrome and the triad syndrome. In about 3 of 4 patients with the prune belly syndrome, there are associated malformations of the cardiopulmonary, gastrointestinal, and orthopedic systems.
Article
The congenital triad of abdominal muscle deficiency, severe urinary tract abnormality, and cryptorchidism forms a rare but well-defined clinical condition popularly known as the “prune belly syndrome” (PBS) [1–10]. The term “prune belly” is descriptive of the characteristic wizened, dried-plum appearance in the newborn and young infant (Fig. 1). The peculiar and, in “classical” cases, pathognomonic aspect of the thin, transparent, redundant abdominal skin, which is loose rather than stretched, nestling to the wobbly intestines at birth, becomes less marked with advancing age. With age, the wrinkles flatten out as the subcutaneous fat and intraabdominal content increase, expanding further the flaring and floppy flanks and the paunch. In addition to the therapeutic challenge presented by the PBS, its etiology and pathogenesis have been controversial. Earlier studies suggested a mesenchymal developmental arrest during the 6th to 7th week of gestation leading to coordinated defects of dependent structures [11, 12]. Recently, an old hypothesis has been resurrected and extended [13–15]. It explains the morphologic characteristics of the PBS as sequelae of an intrauterine distension of the abdomen, usually by enlargement of the bladder due to an obstruction of the proximal urethra [16–19]. Operative removal of the obstructing tissue such as an urethral valve would under these circumstances be a logical measure in the affected newborn or infant. Our personal experience with 14 patients with PBS and a critical analysis of the literature do not support the hypothesis of a secondary pathogenetic sequence arising from a primary obstructive uropathy. PBS and the “urethral obstruction malformation complex” [14] are different conditions, which can be separated by clinical, radiographic, endoscopic, and histologic evaluation. This distinction determines the choice of the most effective form of therapy.
Article
The prune-belly syndrome comprises a constellation of well-established physical findings, yet the cause and management remain controversial. This review focuses on the current understanding of its pathogenesis and characterizes the fetal and neonatal diagnosis and management. Other associated anomalies are discussed to understand better the factors affecting treatment and prognosis as these patients grow into childhood and beyond.
Article
The pathogenesis of lower urinary tract obstruction is disputed, particularly its relation to both abnormal prostatic development and the prune belly syndrome (PBS). In an attempt to clarify this issue we examined 11 males (17-38 weeks gestation) with PBS who were autopsied at our institution. The lower urinary tract was embedded intact and prepared as serial histologic sections. Of the 11 cases, 8 demonstrated mechanical obstruction of the lower urinary tract. In five of these eight cases, a "flap-valve" structure was formed by an abnormal angulation between the prostatic and penile portions of the urethra. These had dilated, thin-walled bladders and prostates and moderate to severe renal dysplasia. One of the eight cases had a valve-like obstruction at the level of the mid-prostatic urethra associated with a complex cloacal malformation and a thin-walled bladder, another case had an epithelial plug at the penile meatus, and the last of the eight cases had a posterior urethral valve. The three remaining cases showed no mechanical obstruction. However, each had megacystis with marked thickening, interstitial fibrosis, and disarray of smooth muscle bundles in the bladder wall. In 10 cases, the prostate had no or only sparse, flattened glands. These results suggest that the abnormal development of the prostate in PBS may be explained as a pressure-induced dysplasia rather than a primary maldevelopment. The findings further suggest that abnormal prostatic development and the prune belly syndrome may arise from either anatomic obstruction of various types or functional obstruction from megacystis.
Article
To examine the prevalence of chromosomal defects and outcome of fetuses with megacystis at 10-14 weeks of gestation. At the 10-14-week scan fetal megacystis was defined by a longitudinal bladder diameter of 7 mm or more. In 145 such fetuses the fetal karyotype and pregnancy outcome were examined in relation to the longitudinal diameter of the fetal bladder. Chromosomal defects, mainly trisomies 13 and 18, were present in 30 cases. In the group with longitudinal bladder diameter of 7-15 mm the incidence of chromosomal defects was 23.6% (26/110), whereas in those with bladder diameter > 15 mm the incidence was 11.4% (4/35). The fetal nuchal translucency (NT) was above the 95th centile of the normal range for crown-rump length in a higher proportion of cases with abnormal rather than normal karyotype (76.7% compared to 31.3%; Chi-square P < 0.0001). The expected number of cases of trisomy 21, estimated on the basis of maternal age, gestational age and fetal NT, was 6.2 rather than the observed 2 and the corresponding numbers for trisomies 13 or 18 were 4.2 for expected and 24 for observed. In the chromosomally normal group with longitudinal bladder diameter of 7-15 mm follow-up scans demonstrated spontaneous resolution of the megacystis in 90% of the cases and enlargement of the megacystis and/or the development of echogenic kidneys in 10%. In contrast, none of the cases with bladder diameter > 15 mm demonstrated spontaneous resolution of the megacystis. In fetal megacystis with longitudinal bladder diameter of 7-15 mm there is a risk of about 25% that the fetus will have a chromosomal defect but in the chromosomally normal group there is spontaneous resolution of the megacystis in about 90% of cases. If the bladder diameter is > 15 mm the risk of chromosomal defects is about 10% and in the chromosomally normal group the condition is invariably associated with progressive obstructive uropathy.
Article
Prune-belly syndrome is a congenital disorder characterized by abdominal wall musculature deficiency, urinary tract anomalies, and bilateral cryptorchidism. Because of the defect in the musculature, the abdominal skin has a peculiar wrinkled appearance. The syndrome is commonly associated with pulmonary, skeletal, cardiac, and gastrointestinal defects. Developmental delays and growth retardation have also been reported. The incidence of prune belly syndrome is approximately 1:40,000 live births. Over 95% of patients are men. Urinary tract disease is the major prognostic factor, with the complications of pulmonary hypoplasia and end stage renal disease resulting in a mortality rate of 60%. Treatment involves surgical correction of the abdominal wall defect and urinary tract abnormalities, early orchiopexy, and supportive management of associated defects.
  • Dc Guo
  • H Pannu
  • V Tran-Fadulu
  • Cl Papke
  • Rk Yu
  • N Avidan
  • S Bourgeois
  • Al Estrera
  • Hj Safi
  • E Sparks
  • D Amor
  • L Ades
  • V Mcconnell
  • Ce Willoughby
  • D Abuelo
  • M Willing
  • Ra Lewis
  • Dh Kim
  • S Scherer
  • Pp Tung
  • C Ahn
  • Lm Buja
  • Cs Raman
  • Ss Shete
  • Dm Milewicz
Guo DC, Pannu H, Tran-Fadulu V, Papke CL, Yu RK, Avidan N, Bourgeois S, Estrera AL, Safi HJ, Sparks E, Amor D, Ades L, McConnell V, Willoughby CE, Abuelo D, Willing M, Lewis RA, Kim DH, Scherer S, Tung PP, Ahn C, Buja LM, Raman CS, Shete SS, Milewicz DM. 2007. Mutations in smooth muscle alpha-actin (ACTA2) lead to thoracic aortic aneurysms and dissections. Nat Genet 39:1488–1493.