先天性厚甲症Ⅰ型一家系K6a基因突变检测

摘要

Objective: To investigate pathogenic mutation of the K6a gene in a Chinese pedigree with pachyonychia congenita type 1 (PC - 1). Methods: Genomic DNA was extracted from peripheral blood of the patient with PC - 1 and 100 unrelated normal persons. The whole coding region of the K6a gene was amplified using long-range polymerase chain reaction (PCR) , and then, nested PCR was used to amplify the mutation 'hot-spot' of the K6a gene. The PCR products were directly sequenced to detect the mutation. Results: A missense mutation L468Q in the helix 2B domain of the K6a polypeptide was identified in the patient, but not in the healthy individuals from family and 100 unrelated normal individuals. Conclusions: A mutation of L468Q in this family is identified, which provided further evidence that the helix boundary motif sequences of K6a is a mutation hot - spot for PC -1.%目的:研究先天性厚甲症Ⅰ型(Pachyonychia congenita type 1,PC-1)一家系K6a基因突变.方法: 提取PC-1患者和100名正常对照的外周血白细胞基因组DNA,采取长片段聚合酶链反应(PCR)扩增基因的全部编码序列,然后以产物为模板,采用巢式PCR扩增突变热点区,最后通过DNA直接测序确定基因突变位点和类型.结果: DNA测序发现患者K6a基因第1403位核甘酸由胸腺嘧啶(T)变为腺嘌呤(A),导致K6a的2B螺旋区末端第468位密码子由亮氨酸(L)变为谷氨酰胺(Q).而该家系中的正常人及100名正常对照均未发现此突变.结论:该患者存在角蛋白K6a L468Q突变,进一步证明了螺旋边界序列是角蛋白K6a基因的突变热点区.