Optic atrophy type 1 (OPA1, MIM 165500) is a dominantly inherited optic 
neuropathy occurring in 1 in 50,000 individuals that features progressive loss 
in visual acuity leading, in many cases, to legal blindness. Phenotypic 
variations and loss of retinal ganglion cells, as found in Leber hereditary 
optic neuropathy (LHON), have suggested possible mitochondrial impairment. The 
OPA1 gene has been localized to 3q28-q29 (refs 13-19). We describe here a 
nuclear gene, OPA1, that maps within the candidate region and encodes a 
dynamin-related protein localized to mitochondria. We found four different OPA1 
mutations, including frameshift and missense mutations, to segregate with the 
disease, demonstrating a role for mitochondria in retinal ganglion cell 
pathophysiology.