Abstract

Initially identified as a cause of myopathy, mitochondrial dysfunction is now recognized as a relatively common cause of multisystem disease, affecting not only the central and peripheral nervous system but also other organs. Some of the characteristic clinical, pathological and molecular findings are summarized and illustrated

NEUROLOGICAL FEATURES

• Chronic progressive external ophthalmoplegia (CPEO)

• Pigmentary retinopathy

• Optic atrophy

• Epilepsy (myoclonus)

• Dementia

• Encephalopathy

• Leigh’s syndrome

• Stroke-like episodes

• Deafness

• Movement disorder

• Myopathy

• Neuropathy

NON-NEUROLOGICAL FEATURES

• Cardiomyopathy

• Cardiac conduction defects

• Diabetes mellitus

• Short stature

• Endocrine dysfunction

• Gut hypomotility

• Hepatic failure

• Fanconi syndrome

• Lipomatosis

CHRONIC PROGRESSIVE EXTERNAL OPHTHALMOPLEGIA

The patient is first looking ahead (Fig. 1(a)) and then attempting to look to the far left (Fig. 1(b)), but the range of movement is limited. Ptosis is slowly progressive and may be asymmetric (myasthenia gravis