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Congenital centronuclear (myotubular) myopathy. A clinical, pathological and genetic study in eight children
Insights
This study describes eight children with centronuclear (myotubular) myopathy, identifying distinct genetic patterns and clinical presentations. Findings support classifying this myopathy into three subgroups for better diagnosis and genetic counseling.
Area of Science:
- Genetics
- Neurology
- Pediatrics
Background:
- Centronuclear (myotubular) myopathy is a rare congenital muscle disorder.
- The disorder exhibits significant variability in clinical presentation and inheritance patterns.
Purpose of the Study:
- To describe clinical and genetic features of eight unrelated children with centronuclear (myotubular) myopathy.
- To propose a classification system for centronuclear (myotubular) myopathy based on clinical severity and inheritance.
- To provide guidance for genetic counseling in affected families.
Main Methods:
- Clinical case series of eight children diagnosed with centronuclear (myotubular) myopathy.
- Family history and genetic analysis (autosomal recessive, X-linked, autosomal dominant) in affected families.
- Clinical examination and muscle biopsy for relatives to identify mild cases.
Main Results:
- Patients ranged from 5 days to 12 years at diagnosis, with intrauterine onset in six and severe birth asphyxia in five.
- Facial weakness and ophthalmoplegia were common findings.
- Genetic analysis suggested autosomal recessive inheritance in two families and X-linked inheritance in five families.
Conclusions:
- Centronuclear (myotubular) myopathy can be classified into three subgroups: severe neonatal X-linked recessive, infantile/juvenile autosomal recessive, and milder autosomal dominant types.
- Classification should integrate severity, presentation, and genetic pattern.
- Examination of relatives for subtle clinical and biopsy findings is crucial for genetic counseling.
Abstract:
Eight unrelated children with centronuclear (myotubular) myopathy are described, ranging in age at the time of diagnosis from 5 days to 12 years. Six had an intrauterine onset and 5 were severely asphyxiated at birth. All had facial involvement and 6 had ophthalmoplegia. Detailed study of the parents in 7 of the families suggested an autosomal recessive inheritance or sporadic occurrence in 2 and X-linked inheritance in 5. Classification in this very variable disorder should be based on severity and mode of presentation together with the genetic pattern, allowing three subgroups to be defined: a severe neonatal X-linked recessive type, a less severe infantile or juvenile autosomal recessive type and a milder autosomal dominant type. For genetic counselling, available relatives should be examined for mild degrees of clinical involvement and morphological abnormalities on needle muscle biopsy.