Juvenile Leigh's encephalomyelopathy with peripheral neuropathy, myopathy, and cardiomyopathy

A child with typical histopathologic changes of Leigh's subacute necrotizing encephalomyelopathy presented with a chronic demyelinating neuropathy. During her 11-year course, she developed an unusual myopathy and cardiomyopathy in addition to many of the previously described manifestations of Leigh's disease. Despite an extensive evaluation, the biochemical basis of her condition was never identified. This case demonstrates another unique constellation of clinical alterations associated with subacute necrotizing encephalomyelopathy, and that chronic demyelinating neuropathy can be an important initial presentation of the disease.