Adult-onset ataxia and polyneuropathy caused by mitochondrial 8993T→C mutation

The 8993T→C mutation in mitochondrial DNA (mtDNA) has been described previously to be associated with infantile‐ or childhood‐onset phenotypes, ranging from Leigh's syndrome to neurogenic weakness, ataxia, and retinitis pigmentosa syndrome. We report a kindred with adult‐onset slowly progressive ataxia and polyneuropathy and with the heteroplasmic 8993T→C mutation. Our findings suggest that the 8993T→C mtDNA mutation should be considered in the differential diagnosis of nondominant adult‐onset ataxia and axonal neuropathy. Ann Neurol 2005;58:337–340