| Main clinical features
|
progressive muscle weakness affecting the proximal and axial muscles of the upper and lower limbs; age at onset is highly variable, usually in the first decade, although onset in the fourth decade has also been reported; this disorder can be rapidly progressive or show a slower course
most patients have limited ambulation or become wheelchair-bound within a few decades, and respiratory insufficiency commonly occurs
laboratory studies show increased serum creatine kinase and elevated fasting blood glucose levels, although cholesterol is normal
EMG shows a myopathic pattern; muscle biopsy is generally unremarkable |