Leber's hereditary optic neuropathy in women

Four women, from three families, are presented who developed severe bilateral optic nerve disease. A diagnosis of Leber's hereditary optic neuropathy (LHON) was made when male family members became affected. The disease ran a similar course in men and women with severe and permanent reduction in vision. Two women had been told that they suffered from multiple sclerosis. With recent advances in diagnostic techniques it should be possible to distinguish between these two conditions. Although LHON may be underdiagnosed in women, there does seem to be a male preponderance of the disease in most European pedigrees. Recent work supports the assumption that LHON is transmitted via cytoplasmic DNA; however, this does not explain why men are more likely to be affected, nor why only a minority of those carrying the defect develop the disease.