[Leber's hereditary optic neuropathy: DNA-diagnosis and clinico-genetic comparisons in 12 families].

Leber's hereditary optic neuropathy (LHON) is a worldwide spread neuro-ophthalmologic disease characterized by immediate pronounced visual reduction with a picture of retrobulbar neuritis, following by optic atrophy. The disease is caused by mitochondrial DNA mutations. Molecular genetic structure of 12 families, including 26 LHON patients, 13 of them being examined, is presented. All of the main primary mutations have been found: the most frequent 11778A (in 10 families), 3460A and 14484C (each in 1 family). In 5 families, the disease was clearly hereditary. Men predominated among the patients, that indicated a reduction of the gene penetrance in women. The most frequent age at the disease onset is 18-25 years. Clinico-genealogical LHON mechanisms correlate with mutation type. Molecular genetic mechanisms of the disease and possible environmental factors, influencing the gene penetrance, are discussed.