Abstract
Purpose: :
To report a novel mutation of the OPA1 gene in a Japanese patient (22–year–old male), with dominant optic atrophy (DOA) and to describe the clinical features of this patient.
Methods: :
Standard ocular examinations were performed on the proband and his two non–affected relatives. The DNA sequence of all exons and splice sites of the OPA1 gene was evaluated to detect mutations using direct sequencing. The single nucleotide polymorphisms found by direct sequencing was confirmed by the single nucleotide primer extension method.
Results: :
Clinically, the patient had reduced visual acuity during his elementary school days, with his best corrected visual acuity being 6/36 OD and 6/60 OS. The patient had bilateral temporal atrophy of the optic nerve, and his visual field was normal. Color vision was tested using a 15–hue Farnworth’s panel. The patient made a disorganized classification with a specific confusion in the blue–yellow axis, suggesting tritanopia. The proband had a nonsense mutation of the OPA1 gene in exon 2 (C to T at 154), which resulted in an instant termination of translation (R52X). This mutation was not detected in his two non–affected relatives.
Conclusions: :
A novel mutation of the OPA1 gene was detected in a Japanese patient with DOA. OPA1 is a mitochondrial dynamin–related GTPase implicated in the formation and maintenance of the mitochondrial network. To date, 96 mutations have been identified, but the genotype–phenotype correlation is unclear. This case study will contribute to a better understanding of DOA.
Keywords: mutations • neuro-ophthalmology: optic nerve • genetics