两个家系中X连锁视网膜色素变性的RP2基因无义突变

Identification of a nonsense mutation causing X-linked RP2 in two Chinese families

目的 检测引起 2个家系产生X连锁视网膜色素变性的RP2基因突变。方法 根据RP2基因外显子和内含子DNA序列合成 8对引物 ,以人基因组DNA为模板 ,PCR扩增出包含RP2基因所有外显子的 8个片段。扩增产物纯化后直接测序。通过比较病人和正常人相应的DNA序列 ,检测基因突变位点。结果 在 2个家系中首次检测到RP2基因的同一个无义突变 35 8C→T。突变位于RP2基因的第 2外显子。它使该基因编码精氨酸的遗传密码CGA变为终止密码TGA ,引起发病。结论 该突变的检出有助于RP2蛋白的功能分析和X连锁视网膜色素变性的基因诊断。

Objective To detect mutations of the RP2 gene in two Chinese families with X linked retinitis pigmentosa (XLRP). Methods Eight pairs of primers designed from exon and intron sequence of the RP2 gene were used for the amplification of eight segments which encompass all exons of the gene. PCR were carried out with human genomic DNA as the template. The PCR products were sequenced after being purified. Mutation was identified by comparing DNA sequences of patients with that of normal controls. Results The mutation 358C→T was detected in exon 2 of the RP2 gene in both families. It changed the codon CGA for Arginine to a terminator codon TGA and causes retinitis pigmentosa in the two families. Conclusion The mutation 358C→T is useful in analyzing the function of RP2 protein and gene diagnosis of XLRP.