[Childhood Leber hereditary optic neuropathy. A case of a 6-year-old girl with loss of vision].

Leber hereditary optic neuropathy, also known as hereditary optical atrophy, is passed on by the mother. It involves a papilledema and mostly affects young people. It is a mitochondrial DNA disease due to the mutation of the NADH dehydrogenase enzyme. Mutations are not sufficient to cause visual loss. Indeed, some individuals accommodate with mutations but do not express the disease. The heteroplasmic or homoplasmic character of the mutation among patients explains why they develop the disease or not even though they carry the mutation. Symptomatology starts with a central vision loss: a painless scotoma. The disease can progress either toward progressive vision loss, blindness, or spontaneous improvement. We report the rare case of a 6-year-old girl presenting a decline in central visual acuity. The genetic study revealed the presence of the G11778A primary mutation. The physiopathogenic mechanism, the genetic hypothesis of the female form, diagnostic means, and treatment options will be discussed.