Adult-onset myoclonus ataxia associated with the mitochondrial m.8993T>C "NARP" mutation.

Abstract

Mitochondrial dysfunction is an important cause of neurological disease. Mitochondrial disease can present at any age, and the clinical features are extremely varied. The mitochondrial DNA (mtDNA) m.8993T>C mutation is usually encountered either in association with Leigh syndrome1 or the syndrome of neuropathy, ataxia, and retinitis pigmentosa (NARP).2 We describe severe, late‐onset myoclonus ataxia related to the m.8993T>C mutation.