| Main clinical features
|
congenital myopathy with slowly progressive muscular weakness and wasting, involving mainly limb girdle, trunk, and neck muscles but may also affect distal muscles, ptosis and limitation of eye movements frequent, may be present during childhood or adolescence or may not become evident until the third decade of life, and some affected individuals become wheelchair-bound in their fifties
at histology, high frequency of centrally located nuclei in a large number of extrafusal muscle fibers (which is the basis of the name of the disorder), radial arrangement of sarcoplasmic strands around the central nuclei, and predominance and hypotrophy of type 1 fibers |