Rab3Gap1 mutations cause Warberg microsyndrome, a disease characterised by microcephaly, microphthalmia, microcornia, cataracts, optic atrophy, cortical dysplasia, mental retardation, spastic diplegia, and hypogonadism (Morris-Rosendahl et al., 2010;Aligianis et al., 2005). Here, RAB3GAP1 is linked to hereditary optic atrophy.