Analysis of peripherin/RDS gene for Japanese retinal dystrophies

We studied 133 Japanese patients with retinal dystrophies to detect peripherin/RDS (retinal degeneration slow) gene defects. The patients analyzed included 52 with autosomal dominant retinitis pigmentosa, 36 with autosomal recessive retinitis pigmentosa, 3 with simplex retinitis pigmentosa, 12 with cone-rod dystrophy, 5 with rod-cone dystrophy, 3 with vitelliform macular dystrophy (Best's disease), 4 with macular dystrophy, 2 with cone dystrophy, 2 with fundus flavimaculatus, 2 with fundus albipunctatus, and 12 with retinitis pigmentosa with macular degeneration as well as 40 unrelated normal persons. Three exons of the peripherin/RDS gene cut into 150-200 base-pair fragments were amplified by polymerase chain reaction and screened by single-strand conformation polymorphism. The DNA fragments with any suspected variations were directly sequenced. Eight point mutations were detected. Among them, two missense mutations at codons 304 and 338 result in an amino acid substitution of glutamine for glutamic acid and aspartic acid for glycine, respectively. However, they were not cosegregated with the diseases, and these mutations were also commonly found in normal controls. For these controls, the proportion of transversion from G to C at codon 304 (GAG-->CAG) and transition from G to A at codon 338 (GGC-->GAC) were 0.192 +/- 0.045 and 0.173 +/- 0.053, respectively. Our results suggest that a peripherin/RDS gene mutation might be rare in Japanese patients.