一个X-连锁视网膜色素变性中国家系的RPGR基因的新突变

目的 对中国人X-连锁视网膜色素变性一家系进行分子遗传学检测，报告RPGR基因突变。方法 首先对该家系X染色体进行致病基因的连锁分析，然后用单链构象多态性技术和直接DNA测序方法进行基因突变分析。结果 连锁分析在多态性微卫星遗传标记DXSS012和DXS8025产生正的Lod值分别为2．41（Zmax=2．40，θ=0）和1．26。进一步单倍型分析确定该家系致病基因位于Xp21．1，与RP3连锁。用RPGR基因突变分析，在外显子ORF15＋483－484发现GA缺失，引起阅读框架的改变，该基因缺失突变在家系中共分离。结论 报告了中国人X-连锁视网膜色素变性RPGR基因外显子ORF15＋483-484的GA缺失突变，丰富了中国人RPGR基闪突变谱，为今后研究X-连锁视网膜色素变性的基因奠定基础。

A novel RPGR gene mutation in a Chinese family with X-linked dominant retinitis pigmentosa

OBJECTIVE: To report a novel mutation in RPGR gene in a Chinese family with X-linked dominant retinitis pigmentosa(XLRP). METHODS: Genetic linkage analysis was performed on the known genetic loci for XLRP with a panel of polymorphic markers, then the mutations were identified by single-strand conformation polymorphism(SSCP) and direct sequencing. RESULTS: Significant two-point Lod score was generated using marker DXS8025 (Zmax=2.4, theta =0). The disease gene locus was confined to Xp21.1 with further analysis of genetic linkage and haplotype. Mutations screening of RPGR gene in this family revealed a GA deletion at ORF15+483-484 which caused the open reading frameshift. This novel mutation co-segregated with the affected members of the pedigree, but it was not present in the unaffected relatives. CONCLUSION: The above finding expands the spectrum of RPGR mutations causing XLRP in Chinese family and is useful for further genetic consultation and genetic diagnosis.