Overview
Fatal infantile hypertonic myofibrillar myopathy is an extremely rare and severe muscle disease that affects babies from birth or very early infancy. This condition belongs to a group of disorders called myofibrillar myopathies, which involve the breakdown and abnormal buildup of proteins inside muscle fibers. In this particular form, affected infants develop abnormally stiff and rigid muscles (hypertonia), meaning their muscles are constantly tight and difficult to move. The disease progresses rapidly and severely impairs the baby's ability to move, breathe, and feed. Babies with this condition typically show signs of muscle stiffness and weakness very early in life. They may have difficulty breathing on their own and often require respiratory support. Feeding problems are common because the muscles needed for swallowing are also affected. The disease follows a rapidly progressive course, and sadly, it is fatal in infancy, usually within the first year of life. There is currently no cure or disease-modifying treatment for this condition. Care is focused on supportive measures, including respiratory support, nutritional assistance, and comfort care. Because this disease is so rare, research is very limited, and families are encouraged to work closely with specialists in neuromuscular diseases and genetics to understand the condition and available supportive options.
Key symptoms:
Severe muscle stiffness from birthMuscle weaknessDifficulty breathingFeeding difficultiesPoor or absent movementFailure to thrive or poor weight gainRigid body postureReduced or absent reflexesRespiratory failureInability to reach developmental milestones
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for Fatal infantile hypertonic myofibrillar myopathy.
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Specialists
View all specialists →No specialists are currently listed for Fatal infantile hypertonic myofibrillar myopathy.
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 Fatal infantile hypertonic myofibrillar myopathy.
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Caregiver Resources
NORD Caregiver Resources
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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.What is the expected course of this disease for my baby?,What supportive treatments are available to keep my baby comfortable?,Should we pursue genetic testing, and what will the results mean for our family?,What is the chance of this happening again in a future pregnancy?,Can you refer us to palliative care and family support services?,Are there any research studies or clinical trials we should know about?,What emergency signs should we watch for at home?
Common questions about Fatal infantile hypertonic myofibrillar myopathy
What is Fatal infantile hypertonic myofibrillar myopathy?
Fatal infantile hypertonic myofibrillar myopathy is an extremely rare and severe muscle disease that affects babies from birth or very early infancy. This condition belongs to a group of disorders called myofibrillar myopathies, which involve the breakdown and abnormal buildup of proteins inside muscle fibers. In this particular form, affected infants develop abnormally stiff and rigid muscles (hypertonia), meaning their muscles are constantly tight and difficult to move. The disease progresses rapidly and severely impairs the baby's ability to move, breathe, and feed. Babies with this condit
How is Fatal infantile hypertonic myofibrillar myopathy inherited?
Fatal infantile hypertonic myofibrillar myopathy follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Fatal infantile hypertonic myofibrillar myopathy typically begin?
Typical onset of Fatal infantile hypertonic myofibrillar myopathy is neonatal. Age of onset can vary across affected individuals.