两例疑为X连锁型视网膜色素变性家系的单倍型分析研究

目的应用遗传连锁分析方法对X连锁型视网膜色素变性家系进行分析,定位其致病基因的所在位点.方法选取已知X连锁视网膜色素变性候选基因附近的短串联重复序列多态性标记(short tandem repeat polymorphism, STRP),即在RP2、RP3、RP6、RP23和RP24处分别选取具有高信息量的微卫星位标,对2例疑似为X连锁型视网膜色素变性家系进行遗传连锁分析;通过对家系成员的单倍型分析,并进行两点法连锁分析,确定其致病基因所在染色体的大致位置.结果 2例家系在DXS 993处得到的最大LOD值分别为:1.18和1.03;在DXS 1068处得到的最大 LOD值分别为:0.58和-2.69;在DXS 1214处得到的最大LOD值分别为:-2.33和-2.45;在DXS 8051处得到的最大LOD值分别为:-2.34和-2.51;在DXS 8043处得到的最大LOD值分别为:-2.23和-2.62.结论 ZCF家系的致病基因,可能不在RP3、RP6、RP23或RP24位点;而对于FYJ家系,我们则怀疑致病基因位于RP2位点,但也不排除与RP3连锁;用遗传连锁分析方法对确定致病基因所在染色体的范围起到重要的作用.

Haplotype analysis of two families with X-linked retinitis pigmentosa

Objective To identify the disease locus in X-linked retinitis pigmentosa (RP) families using genetic linkage analysis. Methods Five microsatellite markers were selected from the RP2, RP3, RP6, RP23 and RP24 gene loci, respectively. Haplotype analysis for two X-linked RP families was performed to determine the critical region. Two-point linkage analysis was performed using MLINK program. Results In FYJ and ZCF X-linked RP families, the LOD score was 1.18 and 1.03 at DXS 993, 0.58 and -2.69 at DXS 1068, -2.33 and -2.45 at DXS 1214, -2.34 and -2.51 at DXS 8051, -2.23 and -2.62 at DXS 8043. Conclusion The phenotype of ZCF family is not caused by mutation of RP3, RP6, RP23, RP24 gene, and FYJ family may be linked to RP2 or RP3 gene.