Autosomal dominant optic atrophy (OPA, MIM 165500) is an eye disease characterised by variable optic atrophy and reduction in visual acuity. It has an insidious onset in the first decade of life and is clinically highly heterogeneous. It is associated with a centrocecal scotoma of varying size and density and an acquired blue-yellow dyschromatopsia. Recent studies of three large Danish pedigrees have mapped a gene for dominant optic atrophy (OPA1) to a 10 cM region on chromosome 3q, between markers D3S1314 and D3S1265 (3q28-qter). Genetic linkage analysis in five British pedigrees confirms mapping to chromosome 3q28-qter. Haplotype analysis of a seven generation pedigree positions the disease causing gene between loci D3S3590 and D3S1305, corresponding to a genetic distance of 2 cM. This represents a significant linkage refinement and should facilitate positional cloning of the disease gene.