Myofibrillar myopathy
Miopatia miofibrilar
CategoryDefinition
Myofibrillar myopathies are a heterogeneous group of disorders, characterised by the pathologic finding of myofibrillar disruption on electron microscope with a spectrum of histological abnormalities including excessive desmin accumulation in muscle fibres.
Diagnostic Criteria
Signs & symptoms: Myofibrillar myopathy is characterized by slowly progressive weakness that can involve both proximal and distal muscles. Wide spectrum of clinical phenotypes. Distal muscle weakness is present in about 80% of individuals and is more pronounced than proximal weakness in about 25%. A minority of individuals experience sensory symptoms, muscle stiffness, aching, or cramps. Peripheral neuropathy is present in about 20% of affected individuals. Overt cardiomyopathy is present in 15%-30%.
Most affected individuals develop weakness between 25-45 years of age, however weakness may be noticeable early in infancy or in late adlthood.
Exclusions
- Myasthenia gravis or certain specified neuromuscular junction disorders
- Secondary myopathies