In the year 2000, the human OPA1 gene came to attention, as heterozygous mutations were associated with dominant optic atrophy (DOA) (1, 2), a blinding disorder originally described by the Danish ophthalmologist Paul Kjer in 1959, which usually leads to optic atrophy in the first decade of life (3). Here, OPA1 is linked to hereditary optic atrophy.