Overview
Megaconial congenital muscular dystrophy (also known as megaconial myopathy or congenital muscular dystrophy with mitochondrial structural abnormalities) is a very rare inherited muscle disease that begins in early childhood. The name 'megaconial' refers to the unusually large mitochondria (the energy-producing structures inside cells) that are found in muscle tissue of affected individuals. This disease is caused by mutations in the CHKB gene, which provides instructions for making an enzyme important for building cell membranes and maintaining healthy mitochondria. Children with this condition typically show muscle weakness from an early age, often noticed as delayed motor milestones such as late walking. The weakness mainly affects the muscles closest to the body's center, like the shoulders and hips. Many children also develop intellectual disability, which can range from mild to moderate. Some individuals may experience dilated cardiomyopathy (an enlarged, weakened heart), seizures, and autistic features. The brain may show structural changes visible on MRI scans. There is currently no cure for megaconial congenital muscular dystrophy. Treatment focuses on managing symptoms and supporting quality of life. This includes physical therapy to maintain mobility, occupational therapy, speech therapy, and educational support. Heart function should be monitored regularly. Seizures, if present, are treated with standard anti-seizure medications. A team of specialists working together provides the best care for affected individuals.
Also known as:
Key symptoms:
Muscle weakness, especially in shoulders and hipsDelayed motor milestones such as late walkingIntellectual disability (mild to moderate)Difficulty running or climbing stairsEnlarged, weakened heart (dilated cardiomyopathy)SeizuresAutistic-like behaviorsSpeech and language delaysWaddling gait or difficulty with balanceElevated creatine kinase levels in bloodBrain abnormalities seen on MRIMuscle wasting over timeLearning difficulties
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Infantile
Begins in infancy, roughly 1 month to 2 years old
Treatments
No FDA-approved treatments are currently listed for Megaconial congenital muscular dystrophy.
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Specialists
View all specialists →No specialists are currently listed for Megaconial congenital muscular dystrophy.
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 Megaconial congenital muscular dystrophy.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
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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.How severe is my child's muscle involvement, and what can we expect over time?,Does my child have any heart involvement, and how often should the heart be checked?,What therapies (physical, occupational, speech) should we start right away?,Are there any clinical trials or research studies my child might be eligible for?,What educational supports should we request from the school?,Should other family members be tested for carrier status?,What emergency signs should I watch for at home?
Common questions about Megaconial congenital muscular dystrophy
What is Megaconial congenital muscular dystrophy?
Megaconial congenital muscular dystrophy (also known as megaconial myopathy or congenital muscular dystrophy with mitochondrial structural abnormalities) is a very rare inherited muscle disease that begins in early childhood. The name 'megaconial' refers to the unusually large mitochondria (the energy-producing structures inside cells) that are found in muscle tissue of affected individuals. This disease is caused by mutations in the CHKB gene, which provides instructions for making an enzyme important for building cell membranes and maintaining healthy mitochondria. Children with this condit
How is Megaconial congenital muscular dystrophy inherited?
Megaconial congenital muscular dystrophy follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Megaconial congenital muscular dystrophy typically begin?
Typical onset of Megaconial congenital muscular dystrophy is infantile. Age of onset can vary across affected individuals.