Mitochondrial DNA mutations in an outbreak of optic neuropathy in Cuba.

Since October 1991, nearly 51,000 Cubans have been afflicted in an outbreak of optic and peripheral neuropathies. To begin an investigation of the possible role of mitochondrial DNA (mtDNA) mutations in the outbreak, we studied mtDNA from 14 affected and two unaffected Cubans for the 12 mutations associated with Leber's hereditary optic neuropathy. Eleven probands (12 patients) had optic neuropathy and two had peripheral neuropathy only. We also studied two unaffected relatives of one proband. We identified two mtDNA mutations, at nucleotides 11778 and 3460, in two of the 11 probands with optic neuropathy. Although this data set is too small to reach statistically valid conclusions, it does suggest that mtDNA mutations might be contributing to the outbreak of optic neuropathy in Cuba.