Mutations in the ACTA2 gene are the most common cause of Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS).
Certain variants, particularly those affecting the arginine 179 (Arg179) position, are strongly associated with the most severe and early-onset forms of the condition.
Other variants, such as those affecting Arg258, as well as mutations in related genes like MYH11, have also been linked to MSMDS.
| Most common gene: | ACТA2 |
| Most frequent and severe variant: | p.Arg179His (R179H) |
| Other ACTA2 variants associated with MSMDS: |
• p.Arg179Cys (R179C) • p.Arg179Leu (R179L) • p.Arg179Ser (R179S) • p.Arg258Cys (R258C) • p.Arg258His (R258H) |
| Other genes reported: | MYH11, MYLK |
ACTA2 plays a key role in the function of smooth muscle throughout the body.
When this gene is altered, smooth muscle cells cannot function properly, affecting multiple organ systems from birth.
This disruption explains why MSMDS presents as a multisystem condition rather than a single-organ disease.
These genetic changes can lead to a wide range of clinical manifestations, including:
Because many of these features can be present early in life, ACTA2-related MSMDS may be identifiable from birth through clinical evaluation and confirmed with genetic testing.
*This content is not intended as a substitute for professional medical advice, diagnosis, or treatment. Should you require medical advice, please contact a qualified medical professional who is familiar with Multisystemic Smooth Muscle Dysfunction Syndrome.
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