A型着色性干皮病中XPAC基因的无义突变  

Nonsense Mutation of XPAC Gene in a Pedigree with Xeroderma Pigmentosum Group A

作　　者：杨勇[1] 卜定方[1] 汪科[1] 涂平[1] 朱学骏[1] 

机构地区：[1]北京大学第一医院皮肤性病科,100034

出　　处：《中华皮肤科杂志》2003年第4期189-191,共3页Chinese Journal of Dermatology

基　　金：北京大学医学部"创建世界一流大学行动计划"青年启动基金资助课题

摘　　要：目的检测国内一A型着色性干皮病家系中XPAC基因的突变。方法PCR扩增XPAC基因的全部外显子,并行DNA测序。针对所发现的突变以DdeⅠ内切酶行限制性片段长度多态性(RFLP)分析。结果PCR结合DNA测序发现患者XPAC基因第5外显子存在异常:第631位碱基由胞嘧啶突变为胸腺嘧啶,使第211位氨基酸由精氨酸变为终止密码(R211X),导致其编码的XPA蛋白缺失了C端的63个氨基酸。其父母皆为杂合子。RFLP结果证实了此突变的存在。结论本A型着色性干皮病家系中存在XPAC基因突变,突变致使XPA蛋白功能缺陷,DNA损伤的修复功能受损,导致临床上出现皮肤老化和癌变。Objective To determine XPAC gene mutation in a Chinese pedigree with xeroderma pigmentosum group A.Methods All exons of XPAC gene were analyzed by PCR-DNA sequencing in the pedigree.The mutations were confirmed by restriction fragment length polymorphism(RFLP).Results By PCR-DNA sequencing,a nonsense mutation of C631T was identified which caused R211X substitution in exon5of XPAC gene.The mutated gene encoded a defective XPA protein truncated by63amino acids in C-terminus.The parents were all heterozygotes.The results were confirmed by RFLP.Conclusions A nonsense mutation is found in XPAC gene of a pedigree of xeroderma pigmentosum group A.This mutation may impair XPA protein function of DNA repair,and as a consequence,cause skin aging and carcinogenesis.

关 键 词：A型着色性干皮病 XPAC基因 无义突变 PCR DNA序列分析 常染色体隐性遗传病 

分 类 号：R758.58[医药卫生—皮肤病学与性病学]