ABSTRACT
Objective To investigate the clinical,genetic and pathological features of familial chronic progressive external ophthalmoplegia (CPEO) type of mitochondrial myopathy.Methods Clinical manifestations, family histories and pathological findings of 21 patients with CPEO type of mitochondrial myopathy from 3 families constellations were analyzed retrospectively.Results All the patients had ptosis and movement disorder of eyeball, with or without myasthenia. An autosomal dominant pattern of transmission was deduced from one family and a maternal transmission appeared most likely in the other two families. The striking and common pathologic findings were presence of ragged red fibers and cytochrome C oxidase (COX) deficiency fibers under microscope. Ultrastructural alterations included subsarcolemmal accumulation of mitochondria, increase of mitochondria with abnormal shape, disarrangement of cristae and paracrystaline inclusion bodies.Conclusions The clinical and pathological features between generations and families seem to be similar. It is suggested that different genetic mode of CPEO may lead to similar clinical and pathological features.