Phenotype associated with an R120X nonsense mutation in the RP2 gene in a Japanese family with X-linked retinitis pigmentosa

We examined a Japanese family with X-linked retinitis pigmentosa (RP) associated with a nonsense mutation, R120X, in the RP2 gene. The 26-year-old proband presented at the age of seven years with a two-year history of night blindness. Visual disability worsened with increasing age. At age 24, visual acuity was 0.08 in both eyes. Testing for refractive error indicated mild myopia. Visual fields showed bilateral-constriction to 10 degrees. He had central macular areolar sclerosis in both eyes. Two maternal uncles had vision of light perception to hand movement in their early forties together with dense bilateral cataracts. The ocular phenotype of this family with R120X was considered severe; reported phenotypes associated with this mutation have not been uniform.