Zebra body myopathy. Clinical, histochemical and ultrastructural studies.

Clinical, electrophysiological and histological evidence is presented of a myopathy not previously described. The patient, aged 15 years, was generally weak and wasted. His condition probably began in utero, but abnormalities of the serum CPK and EMG did not become evident until adolescence. Wide variation in fibre diameter, vacuolation, calcification, increased endomysial connective tissue and intra-fibre splitting were prominent in muscle biopsy sections. Electron microscopy showed numerous rod bodies, fibre disorganisation with loss of Z-bands and occasional honeycomb structures. Frequent zebra bodies were present. Because of the large number of zebra bodies seen, the name "zebra body myopathy" is provisionally proposed.