痒疹样营养不良型大疱性表皮松解症一家系的基因突变

目的 鉴定一痒疹样营养不良型大疱性表皮松解症家系的基因突变,为进一步开展基因诊断和基因治疗奠定基础.方法 应用聚合酶链反应(PCR)、DNA直接测序明确突变位点,根据突变位点设计等位基因特异性引物,用PCR来检测突变位点以及采用逆转录-聚合酶链反应(RT-PCR)和克隆测序进一步确定该家系的致病原因.结果 该家系中患者COL7A1基因的87号外显子存在剪接位点突变,导致87号外显子被剪切,Ⅶ型胶原的胶原区合成后缺少了23个氨基酸.健康对照不存在此突变.结论 COL7A1基因剪接位点的突变是引起该家系临床症状的特异突变,而非多态性改变.

Analysis of COL7A1 Gene Mutation in a Family with Dystrophic Epidermolysis Bullosa Pruriginosa

Objective To identify the COL7A1 gene mutation in a family with dystrophic epidermolysis bullosa pruriginosa. Methods PCR and direct DNA sequencing were employed to determine the mutation sites and mutation types. RT-PCR and cloning sequencing were performed to further identify the pathogeny of this disease. Results A splicing mutation was found in 87 exon of COL7A1 gene which resulted in an inframe deletion of exon 87. Synthesis of α1(VII) collagen polypeptides was internally shortened by 23 amino acids. The mutation was not found in normal controls. Conclusions The splicing mutation of COL7A1 gene is the underlying cause of and specific rather than common polymorphism for the family with dystrophic epidermolysis bullosa pruriginosa subtype.