To report a novel mutation of the OPA1 gene in a Japanese patient with optic atrophy and to describe the clinical features of the patient.Observational case report.Genomic DNA was extracted from leukocytes of four unrelated Japanese patients with optic atrophy. All the exons and splice sites of the OPA1 gene were amplified by polymerase chain reaction and directly sequenced.One patient with optic atrophy had a heterozygous Arg445His mutation in the OPA1 gene. The Arg445His mutation was detected neither in 110 control subjects nor in the patient's healthy family members.A novel mutation of the OPA1 gene, similar to those reported in Western countries, was detected in a Japanese patient with optic atrophy. Mutations of the OPA1 gene may contribute to the development of optic nerve atrophy in Japanese cases of optic atrophy.