Overview
Congenital myasthenic syndrome (CMS), sometimes called congenital myasthenia, is a group of rare inherited disorders that affect the way nerve signals are sent to muscles. In a healthy body, nerves and muscles communicate at a junction called the neuromuscular junction. In CMS, this communication is disrupted because of a genetic change, causing muscles to receive weak or unreliable signals. This leads to muscle weakness that is often present from birth or early childhood, though some forms appear later in life. The weakness in CMS can affect many parts of the body. The muscles around the eyes and eyelids are commonly involved, causing drooping eyelids (ptosis) and double vision. Muscles used for swallowing, breathing, and moving the arms and legs can also be affected. Symptoms often get worse with physical activity and improve with rest. Breathing problems can be serious, especially in babies and young children. There is no cure for CMS, but several medications can help manage symptoms by improving nerve-to-muscle communication. The right treatment depends on which gene is affected, so genetic testing is very important. With proper care, many people with CMS can lead active and fulfilling lives, though some forms are more severe than others.
Also known as:
Key symptoms:
Drooping eyelids (ptosis)Double visionMuscle weakness that gets worse with activityDifficulty swallowingWeak cry or feeding problems in newbornsBreathing difficulties, especially during illness or stressFatigue that comes on quickly during physical activityWeakness in the arms and legsPoor head control in infantsDelayed motor milestones such as sitting or walkingFacial weakness or expressionless faceSlurred or nasal-sounding speechScoliosis (curved spine) in some cases
Clinical phenotype terms (50)— hover any for plain English
Variable
Can be inherited in different ways depending on the underlying gene
Variable
Can begin at different ages, from infancy through adulthood
FDA & Trial Timeline
10 eventsHELP Therapeutics Co., Ltd. — PHASE1, PHASE2
Dermavon Holdings Limited — PHASE2
Dermavon Holdings Limited — PHASE2, PHASE3
Shenzhen Kangzhe Biotechnology Co., Ltd. — PHASE2
Truway Health, Inc.
Third Military Medical University — NA
National Institute of Neurological Disorders and Stroke (NINDS)
HELP Therapeutics Co., Ltd. — PHASE1, PHASE2
The Foundation for Orthopaedics and Regenerative Medicine — PHASE1
argenx — PHASE1
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Congenital myasthenic syndrome.
4 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Rare Disease Specialist
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 Congenital myasthenic syndrome.
Community
No community posts yet. Be the first to share your experience with Congenital myasthenic syndrome.
Start the conversation →Latest news about Congenital myasthenic syndrome
Disease timeline:
New recruiting trial: The Role of the Tumor Molecular Profile (CMS), UGT1A1 Genotype and Beta-glucuronidase Activity of the Intestinal Microbiota for Treatment Efficiency, Toxicity, Survival and Quality of Life in Patients With Metastatic or Unresectable Colorectal Cancer During Irinotecan-based Systemic Treatment
A new clinical trial is recruiting patients for Congenital myasthenic syndrome
New recruiting trial: Phase II Study of CMS-D002 Capsule for Uterine Fibroids With Menorrhagia
A new clinical trial is recruiting patients for Congenital myasthenic syndrome
New recruiting trial: Erythrocytapheresis for Chronic Mountain Sickness
A new clinical trial is recruiting patients for Congenital myasthenic syndrome
New recruiting trial: Assessment of Allogeneic Hematopoietic Cell Transplantation in Medicare Beneficiaries With Multiple Myeloma
A new clinical trial is recruiting patients for Congenital myasthenic syndrome
New recruiting trial: Human Embryonic Stem Cell-Derived Cardiomyocyte Therapy for Chronic Ischemic Left Ventricular Dysfunction
A new clinical trial is recruiting patients for Congenital myasthenic syndrome
New recruiting trial: A Natural History Study in Participants With Congenital Myasthenic Syndromes (CMS) Due to Mutations in DOK7, MUSK, AGRN, or LRP4
A new clinical trial is recruiting patients for Congenital myasthenic syndrome
New recruiting trial: A Prospective Natural History and Outcome Measure Validation Study of Congenital Myasthenic Syndromes
A new clinical trial is recruiting patients for Congenital myasthenic syndrome
New recruiting trial: Patients With Congenital Myasthenic Syndrome Will be Treated With Mesenchymal Stem Cell Exosome Solution
A new clinical trial is recruiting patients for Congenital myasthenic 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.Which gene is causing my CMS, and how does that affect my treatment options?,Which medications are safe for me, and which ones should I avoid?,Do I need breathing tests, and should I use any breathing support at night?,What signs should prompt me to go to the emergency room?,Are there clinical trials or new treatments I should know about?,Should other family members be tested for this condition?,What therapies or support services would help me manage daily life better?
Common questions about Congenital myasthenic syndrome
What is Congenital myasthenic syndrome?
Congenital myasthenic syndrome (CMS), sometimes called congenital myasthenia, is a group of rare inherited disorders that affect the way nerve signals are sent to muscles. In a healthy body, nerves and muscles communicate at a junction called the neuromuscular junction. In CMS, this communication is disrupted because of a genetic change, causing muscles to receive weak or unreliable signals. This leads to muscle weakness that is often present from birth or early childhood, though some forms appear later in life. The weakness in CMS can affect many parts of the body. The muscles around the eye
Are there clinical trials for Congenital myasthenic syndrome?
Yes — 4 recruiting clinical trials are currently listed for Congenital myasthenic syndrome on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Congenital myasthenic syndrome?
7 specialists and care centers treating Congenital myasthenic syndrome are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.