Overview
Multisystemic smooth muscle dysfunction syndrome (MSMDS) is an extremely rare genetic disorder caused by mutations in the ACTA2 gene. This gene provides instructions for making a protein called alpha-smooth muscle actin, which is essential for the proper function of smooth muscle cells throughout the body. Smooth muscles are the muscles you cannot control voluntarily — they line blood vessels, the bladder, the gut, and the airways. Because smooth muscle is found in so many organs, this condition affects multiple body systems. The most serious problems involve the blood vessels, including a characteristic pattern of dilated (widened) and stiff arteries, particularly the aorta. Patients often have a specific brain blood vessel abnormality called Moyamoya disease, which can lead to strokes. Other common features include a fixed, dilated pupil in the eyes (called mydriasis), problems with bladder emptying, reduced gut movement leading to poor digestion, and lung disease. Some patients also have a distinctive pattern of white matter changes in the brain. There is currently no cure for MSMDS. Treatment focuses on managing each affected organ system individually. This may include surgeries to repair blood vessel problems, medications to prevent strokes, and supportive care for bladder and gut issues. Because the disease affects so many systems, patients typically need a team of specialists working together. Early diagnosis is important so that monitoring and preventive measures can be started as soon as possible.
Key symptoms:
Widened or dilated aorta and other large arteriesMoyamoya disease (abnormal blood vessels in the brain)Strokes, including in childhoodFixed, dilated pupils that do not react to lightDifficulty emptying the bladderChronic constipation or poor gut movementLung disease or breathing difficultiesWhite matter abnormalities in the brainPatent ductus arteriosus (a heart defect present at birth)Low blood pressureRecurrent lung infectionsPoor weight gain or failure to thriveDifficulty feeding in infancyCongenital heart defects
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
2 eventsMassachusetts General Hospital
The University of Texas Health Science Center, Houston — PHASE1
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Multisystemic smooth muscle dysfunction syndrome.
2 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Specialists
View all specialists →No specialists are currently listed for Multisystemic smooth muscle dysfunction syndrome.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Multisystemic smooth muscle dysfunction syndrome.
Community
No community posts yet. Be the first to share your experience with Multisystemic smooth muscle dysfunction syndrome.
Start the conversation →Latest news about Multisystemic smooth muscle dysfunction syndrome
Disease timeline:
New recruiting trial: A Retrospective and Prospective Natural History of Genetic Vasculopathies
A new clinical trial is recruiting patients for Multisystemic smooth muscle dysfunction syndrome
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What specific ACTA2 mutation does my child have, and what does it mean for their prognosis?,How often should brain imaging be done to monitor for Moyamoya disease?,What are the warning signs of a stroke that I should watch for at home?,Is surgical revascularization recommended for my child's brain blood vessel problems?,How should we manage bladder and bowel problems on a daily basis?,Are there any clinical trials or research studies we could participate in?,Should other family members be tested for the ACTA2 mutation?
Common questions about Multisystemic smooth muscle dysfunction syndrome
What is Multisystemic smooth muscle dysfunction syndrome?
Multisystemic smooth muscle dysfunction syndrome (MSMDS) is an extremely rare genetic disorder caused by mutations in the ACTA2 gene. This gene provides instructions for making a protein called alpha-smooth muscle actin, which is essential for the proper function of smooth muscle cells throughout the body. Smooth muscles are the muscles you cannot control voluntarily — they line blood vessels, the bladder, the gut, and the airways. Because smooth muscle is found in so many organs, this condition affects multiple body systems. The most serious problems involve the blood vessels, including a ch
How is Multisystemic smooth muscle dysfunction syndrome inherited?
Multisystemic smooth muscle dysfunction syndrome follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Multisystemic smooth muscle dysfunction syndrome typically begin?
Typical onset of Multisystemic smooth muscle dysfunction syndrome is neonatal. Age of onset can vary across affected individuals.
Are there clinical trials for Multisystemic smooth muscle dysfunction syndrome?
Yes — 2 recruiting clinical trials are currently listed for Multisystemic smooth muscle dysfunction syndrome on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.