多发性脂囊瘤患者角蛋白17基因突变的研究

Keratin 17 gene mutation in patients with steatocystoma multiplex

目的 了解多发性脂囊瘤和角蛋白 17基因异常的关系。方法 应用逆转录 聚合酶链反应及其产物直接测序 ,巢式聚合酶链反应及限制性片段长度多态性分析 ,研究多发性脂囊瘤家系中患者囊肿组织cDNA及外周血DNA的角蛋白 17基因突变。结果 囊肿组织显示角蛋白 17基因第 94位密码子 ,42 8碱基发生G→A的突变 ,使原编码的氨基酸由精氨酸变为半胱氨酸 ,即R94C的杂合突变。巢式聚合酶链反应后Acil限制酶谱多态性分析 ,显示患者外周血DNA标本均有一条突变等位基因缺乏该酶酶切位点 ,产生 2 0 0bp的条带 ,另有一条野生型等位基因已被切开 ,形成 2条带 ,分别为10 8bp ,92bp ,进一步证实R94C的突变 ,系杂合性突变。而正常人 10人份及 2 0 0 0人份正常人DNAPool标本 2条等位基因均有Acil的酶切位点 ,只显示 10 8bp和 92bp 2条带。结论 角蛋白 17基因R94C的突变 ,是导致中国人多发性脂囊瘤的遗传学基础之一。

Objective To study the relationship between steatocystoma multiplex (SCM) and keratin 17 gene mutation. Methods The keratin 17 gene mutation in the cDNA of cystic tissue of 5 patients of SCM and in the DNA in peripheral blood of 25 patients with SCM from a SCM family was studied by direct sequencing of the RT PCR products, nested PCR, and restricted fraction length polymorphism (RFLP) analysis. Thirty nine blood specimens from the unaffected members of that family were collected and tested too. Ten DNA pool specimens and other 2000 DNA pool specimens of normal individuals outside that SCM family were used as controls. Results In the base 428, 94 th codon in keratin 17 gene in the cDNA of patients' cystic tissue, R94C mutation, a G→A mutation, was detected Nested PCR, and restricted enzyme Acil polymorphism analysis showed that in the DNA specimens of peripheral blood of patients a mutated allele lacking enzyme cutting locus was detected, thus causing an uncut band with 200 bp while the corresponding allele was cut and caused two bands with 108 bp and 92 bp. In the DNA pool specimens of normal controls only these two bands with 108 bp and 92 bp were observed. Conclusion The R94C mutation in keratin 17 gene is one of the genetic bases of SCM in Chinese. The results of this study provide scientific data for genetic diagnosis and counseling of SCM.