The diagnosis of Leber’s hereditary optic neuropathy (LHON) in 6 female atypical cases seen at Harvard, Emory, and Johns Hopkins Medical Centers required molecular analysis and demonstration of the 11778 mitochondrial DNA mutation for accurate confirmation. Features atypical for LHON included a negative family history, a normal fundus, bitemporal hemianopia, optic disc cupping, and premonitory episodes of transient monocular visual loss. Molecular analysis allows accurate identification of most cases. The 11778 point mutation accounts for 50%. 
COMMENT. In typical cases of LHON, males predominate and the fundus is characterized by circumpapillary telangiectatic microangiopathy and pseudoedema. The diagnosis should also be considered in females with an unexplained optic neuropathy, a negative family history and a normal fundus. Genetic analysis has allowed for a broader view of what constitutes the clinical phenotype of LHON.