基因诊断有汗性外胚层发育不良一家系

目的 对一个仅有甲和毛发损害的外胚层发育不良家系进行基因突变研究,以期确定其致病基因,明确临床诊断.方法 共收集该家系7例患者及15例正常家系成员外周血,提取基因组DNA,采用PCR扩增候选基因K16、K17、K6a、K6b和GJB6基因的整个编码序列,DNA直接测序明确具体的突变位置和方式,通过RT-PCR在mRNA水平验证该家系的致病基因.结果 家系所有患者GJB6基因均存在一个杂合错义突变31G→A,导致N-末端区域第11位甘氨酸被精氨酸替代(即G11R),而家系中的15例正常人DNA测序结果均未发现此突变.来源于先证者皮损组织的cDNA测序结果亦证实存在该突变.结论 该家系患者均存在GJB6基因突变,此基因为已知的有汗性外胚层发育不良的致病基因.

Gene diagnosis in a family with hidrotic ectodermal dysplasia

Objective To confirm the diagnosis and to localize the pathogenic gene of ectodermal dysplasia in a family SUffering from only hair and nail abnormalities.MethodsBlood samples were collected from 7 affected patients and 15 unafiected individuals in the family.Genomic DNA was extracted from blood samples by routine phenol-chloroform methods.The whole coding regions of candidate genes K16,K17,K6a,K6b and GJB6 were amplified by PCR followed by direct sequencing.Then,the gene mutation was further confirmed at mRNA level by RT-PCR.ResultsA heterozygous missense mutation 3 1G→A in the GJB6 gene.which leads to the substitution of glycine by arginine at codon 11(G11R)on the N-terminal of the protein,was detected in all the patients.but in none of the 15 normal individuals in this family.The mutation was also confirmed in the CDNA originating from the proband's skin biopsy.Conelusionn A missense mutation G31A.which has been shown previously to cause hidrotic ectodermal dysplasia(HED),is localized in the GJB6 gene of patients in this family.