Investigation On Genetic Linkage Analysis Of X-linked Retinitis Pigmentosa Using Microsatellite Markers

Background:Retinitis pigmentosa (RP) is a genetically and clinically heterogeneous group of progressive retinal degenerations with an overall incidence of 1 in 3500-4000 in the general population. Most patients with RP typically experience night blindness, a gradual loss of peripheral visual field and eventually loss of central vision due to degeneration of rod photoreceptor cells followed by cone cells. RP exhibits extreme heterogeneity in terms of its severity and mode of inheritance including autosomal dominant , autosomal recessive , X-linked , and digenic modes. So far, at least 32 distinct genetic loci have been implicated in RP, sometimes the same gene gets involved in different inheritance traits. The X-linked form of retinitis pigmentosa (XLRP) is the most severe owing to their early onset and significant vision loss before the fourth decade. By linkage analysis , five XLRP loci have been localised:RP2(Xp11.3),RP3(Xp11.4-21.1),RP6(Xp21.2-21.3),RP23(Xp22),RP24(Xq26-q27). Linkage studies suggest that retinitis pigmentosa GTPase regulator ( RPGR) gene accounts for 70-90% of XLRP.Objects:To identify the disease located in X-linked RP (XLRP) families by genetic linkage analysis. We have collected samples from four ophthalmic outpatient of our hospital whom are doubtful X-linked retinitis pigmentosa families in southwest region (Patients among families were all male and the situation of symptom is severe although the appearance of the disease is early, no evidence predicts the illness of both father and son.). We separate the chromosome segment of disease location among processing transmission were detected, based on the analysis of RP genes, for correlative heritability disease and related locus of disease. It can afford to useful data for those aspects including genetic consultation, clinic diagnosis and therapy. Especially, it is important to detect carrier of female and antenatal diagnosis of fetus.