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Distal myopathy with rimmed vacuoles
I Nonaka1, N Murakami, Y Suzuki
1National Center of Neurology and Psychiatry, Tokyo, Japan. nonaka@ncnaxp.ncnp.go.jp
Neuromuscular Disorders : NMD
|July 23, 1998
Summary
Distal myopathy with rimmed vacuoles is a genetic muscle disorder affecting young adults. This progressive condition leads to significant mobility loss within 12 years due to characteristic rimmed vacuoles in muscle fibers.
Area of Science:
- Neurology
- Genetics
- Pathology
Background:
- Distal myopathy with rimmed vacuoles is an autosomal recessive disorder.
- It primarily affects the anterior tibial muscle and shares genetic linkage with familial inclusion body myopathy on chromosome 9.
- Onset typically occurs in young adults (20-40 years), averaging 26 years.
Purpose of the Study:
- To describe the clinical and pathological features of distal myopathy with rimmed vacuoles.
- To highlight the genetic mapping of the disease locus.
- To elucidate the underlying pathomechanisms.
Main Methods:
- Clinical assessment of patients with distal myopathy.
- Genetic linkage analysis to map the disease gene.
- Histopathological examination of muscle biopsies to identify characteristic features.
Main Results:
- The disease progresses, leading to non-ambulation within 12 years for most patients.
- Pathological findings include prominent rimmed vacuoles in muscle fibers with minimal necrosis or regeneration.
- Nuclear changes with tubulofilamentous inclusions are observed, suggesting a role in myofibrillar degeneration and autophagocytosis.
Conclusions:
- Distal myopathy with rimmed vacuoles is a distinct genetic neuromuscular disorder.
- The pathomechanism involves myofibrillar degeneration and autophagocytosis leading to rimmed vacuole formation.
- Genetic mapping to chromosome 9 provides insights into its relationship with other myopathies.
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