| Research Abstract |
Retinitis Pigmentosa (RP) is a group of hereditary disorders which show bilateral progressive loss of visual acuity and visual field, and night blindness. This is the third most frequent cause (12%) of legal blindness among adult Japanese population. Because of its hereditary nature, researches at the level of genes should be necessary to obtain better understandings of the mechanism of pathogenesis of RP,so that we can specifically design better or more effective modalities of treatment than what we have now.
In this study project, we have performed molecular genetic researches for RP,especially studies for detecting gene abnormalities in Japanese patients with RP.
As the first project, we searched for mutations within the rhodopsin gene and the peripherin/RDS gene in Japanese patients with autosomal dominant RP (adRP) and allied deseases. We employed nonradiosotopic SSCP method that had been established in our past research project (Grant-in-Aid for Scientific Research, B-O354411) to detect putative mutations. To date, we have detected a point mutation in codon 347 (Pro347Leu) in the rhodopsin gene. We also have identified 5 different mutations in the peripherin/RDS gene, and they were Asn244Lys, Asn244His, Tyr184Ser, Arg172Trp, and Val200Glu, respectively. Studies for genotype-phenotype correlation have revealed that Asn244Lys causes rod-cone dystrophy, while Asn244His, Tyr184Ser, and Val200Glu cause cone-rod dystrophy, and Arg172Trp is responsible for macular dystrophy.
As the second part, we have perfoumed linkage analysis for a large family with adRP using several genetic markers. As a result, a positive linkage was obtained between the desease gene and the locus on chromosome 19q (D19S180, Zmax=5.110). Further molecular genetic study will clarify a candidate gene for this locus.
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