Leber's hereditary optic neuropathy (LHON), a maternally inherited dis
ease causing severe bilateral visual loss in young men, is linked to 1
2 point mutations in mitochondrial DNA, the most common of which is at
the nucleotide position 11778, The 11778 point mutation has also been
detected in several patients with possible multiple sclerosis (MS), e
specially women with severe visual loss in both eyes. Because frequent
and severe optic neuropathy is a feature of MS in Japan, we screened
80 Japanese MS patients for the presence of the 11778 mutation by muta
tion-specific polymerase chain reaction. Eighteen women with MS had bi
lateral optic neuropathy, but none had the mutation at 11778, There is
no association between Japanese MS and the 11778 mitochondrial DNA mu
tation.