Related Experiment Videos
Cardiac manifestations of congenital fiber-type disproportion myopathy
B L Banwell1, L E Becker, V Jay
1Department of Pediatric Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
Insights
Congenital fiber-type disproportion myopathy rarely involves the heart. This study reports two children with this condition who developed serious cardiac issues, including dilated cardiomyopathy and atrial fibrillation.
Area of Science:
- Pediatric Cardiology
- Neuromuscular Disorders
- Genetics
Background:
- Congenital fiber-type disproportion (CFTD) is a rare congenital myopathy characterized by specific muscle fiber abnormalities.
- Cardiac involvement is not typically associated with CFTD, distinguishing it from other childhood myopathies.
Observation:
- This report details two pediatric cases presenting with significant cardiac symptoms alongside CFTD.
- One patient developed dilated cardiomyopathy requiring heart transplantation, while the other experienced atrial fibrillation.
Findings:
- Muscle biopsies confirmed CFTD with type I fiber hypotrophy and predominance, excluding other myopathy types.
- Cardiac examination in the first patient revealed dilated cardiomyopathy with hypertrophic myocardiocytes.
Implications:
- These findings suggest a potential link between CFTD and cardiac complications, challenging previous assumptions.
- Annual cardiac assessments, including electrocardiograms, are recommended for children diagnosed with CFTD to enable early detection and management.
Abstract:
Cardiac involvement has not been a reported feature of congenital fiber-type disproportion myopathy. We describe two children, aged 13 years and 1 year, respectively, who presented with serious cardiac symptomatology in conjunction with congenital fiber-type disproportion. One child developed dilated cardiomyopathy and medically intractable congestive heart failure necessitating cardiac transplantation at the age of 13 years. The second (unrelated) child developed atrial fibrillation with rapid atrioventricular conduction requiring treatment with digoxin. Skeletal muscle biopsy findings in both children showed congenital fiber-type disproportion with no evidence of a structural, dystrophic, or metabolic myopathy. Adenosine triphosphatase (ATPase) reacted sections showed type I hypotrophy with a predominance of type I fibers, confirmed by histogram analysis. Examination of the heart from patient 1 at the time of transplantation confirmed dilated cardiomyopathy with hypertrophic myocardiocytes. Although cardiomyopathy is commonly associated with other childhood myopathies, to our knowledge it has not been a feature in reported cases of congenital fiber-type disproportion. We recommend close cardiac assessment, with annual electrocardiograms, of children with congenital fiber-type disproportion.