Main clinical features
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similar to Duchenne muscular dystrophy in the distribution of muscle wasting and weakness, which is mainly proximal, but the course is more benign
age of onset around 12 years; some patients have no symptoms until much later in life; loss of ambulation also varies from adolescence onward, with death usually in the fourth or fifth decade
cramps and myoglobinuria associated with elevated serum levels of creatine kinase, dilated cardiomyopathy with schizophrenia or mental illnesses |