[The study of RDS gene mutation and clinical phenotype in a family with primary retinitis pigmentosa].

OBJECTIVE

To investigate retinal degeneration slow (RDS) gene mutation in a Chinese family with primary retinitis pigmentosa (RP) and the association of the mutation with clinical phenotypes and to explore the pathogenesis of RP.

METHODS

Blood DNA from 2 patients in the same family with RP and 2 normal persons was analyzed by molecular genetic methods. RDS gene mutation was screened out by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. The mutant RDS gene fragment was cloned, then sequenced with an automatic DNA sequencer using a dideoxy chain termination protocol. The phenotype of the patients with the gene mutation were examined and determined by clinical ophthalmologic examinations.

RESULTS

The PCR-RFLP analysis of the RDS gene in 2 patients with RP revealed codon 216 mutation of RDS gene. The mutation was heterozygous, and not found in 2 normal persons as controls. The alteration in the DNA sequence was identified as a heterozygous transversional change of C to T at the second nucleotide in codon 216 of RDS gene, resulting in the amino acid replacement of proline residue with leucine residue (Pro216Leu). The ocular finding of the patients with Pro216Leu mutation of RDS gene included severe visual loss and diffuse distribution of pigmentary changes with macular degeneration.

CONCLUSIONS

The Pro216Leu mutation of RDS gene is found in Chinese patients with RP. The gene mutation is associated with the ocular phenotype, diffuse RP with macular degeneration.