【摘要】 目的研究Ⅰ型先天性甲肥厚患者角蛋白16和6A基因多态现象。方法提取患者及其家系成员外周血基因组DNA,其中1个家系有家族史,有4代7例患者,另一为1个散发病例,无家族史。采用聚合酶链反应扩增KRT16和KRT6A基因的全部编码序列,DNA直接测序,限制性内切酶反应验证。结果有家族史患者KRT16基因DNA测序时发现其2￣3外显子间内含子序列缺失1个碱基G,导致此后的测序结果有很多套峰(出现很多N),经限制性内切酶反应证实是一种多态现象而不是基因突变;同时KRT6A基因第4外显子测序时发现已知的879C>T单核苷酸多态性改变。散发患者的KRT16基因1252C>T单碱基置换,418位密码子CGC被TGC替代,精氨酸变为半胱氨酸(R418C)。但患者表型正常的母亲为1252T纯合子,表型正常的父亲为1252C纯合子,提示1252C>T属于多态性改变;同KRT6A基因的第1外显子检出已知的483T>C和495A>G单核苷酸多态性改变。结论本研究在中国Ⅰ型先天性甲肥厚患者中发现新的、可引起编码氨基酸改变的单核苷酸多态性,同时检测到已知的单核苷酸多态性。更多还原

【Abstract】 Objective To detect the polymorphisms of the KRT6A and KRT16 genes in two Chinese families with pachyonychia congenita type I, one of which had a family history and another was a sporadic case. Methods All exons and their flanking intronic sequences of the two genes were amplified using polymerase chain reaction and then subjected to automatic DNA sequencing. Restriction analysis was applied to confirm the polymorphisms. Results In the pedigree, a nucleotide (G) deletion in intron sequence between exon 2 and exon 3 of KRT16 gene was detected in the patients. This deletion was also found in the unaffected normal individuals of this family. Meanwhile, the patients were also shown to be carriers of one known single nucleotide polymorphism (SNP), 879 C > T (Asp293Asp) in exon 4 of KRT6A gene. In the sporadic case, a novel non-synonymous SNP, 1252 C > T (R418C), was found in KRT16 gene. This patient was heterozygous while her parents were homozygous for 1252 C and 1252 T, respectively. In addition, two known SNPs, 483 T > C (A161A) and 495 A > G (E165E) in exon 1 of KRT6A gene, were found in this patient. Conclusions A novel single nucleotide polymorphism of KRT16 gene which can result in the change of amino acid sequence is firstly reported and some known single nucleotide polymorphisms in KRT16 and KRT6A genes are also found in this study.更多还原