Mitochondrial myopathy with chronic progressive external ophthalmoplegia.

Introduction Mitochondrial diseases are a diverse group with multisystem involvement caused by structural, biochemical or genetic derangement of mitochondria. Cerebral neurones and myocytes which require a high yield of energy are particularly vulnerable to mitochondrial dysfunction and neuromuscular manifestations are common in mitochodrial disorders. We report two cases of mitochondrial myopathy presenting as chronic progressive external ophthalmoplegia.