KRT6a基因N172del新发突变导致I型先天性厚甲症

目的：检测1例I型先天性厚甲症患者KRT6a基因突变。方法：提取该患者及其父母和100名正常对照外周血白细胞基因组DNA，设计针对KRT6a和KRT16基因的特异性引物，PCR扩增KRT6a和KRT16基因的全部外显子，并进行直接测序。结果：PCR扩增结合DNA测序发现该患者KRT6a基因第1外显子存在异常，第514—516位的3个核苷酸AAC缺失，导致第172位氨基酸一天冬酰胺（N）缺失。患者父母及100名正常对照均未发现此突变。未发现KRT16基因突变。结论：KRT6a基因N172del突变可能是导致本例I型先天性厚甲症的致病突变，该突变非遗传自父母，为新发突变。

A N172del de novo mutation in the KRT6a gene is associated with pachyonychia congenita type I

Objective： To detect the KRT6a gene mutation in a sporadic Chinese patient with pachyonychia congenital- I （PC- I）. Methods： Genomic DNA was extracted from whole blood by standard method from a male patient with PC- I and his parents. One hundred normal people were used as controls. All the exons of KRT6a and KRT16 genes were amplified by using polymerase chain reaction （PCR） and subjected to automatic DNA sequencing. Results： Direct sequencing of the PCR products revealed a deletion mutation at nucleotide 514 - 516 （514 - 516delAAC） in exon 1 in the patient, leading to the deletion of the amino acid asparagine at cedon 172 located at the start of 1A domain of K6a. No mutation was found in the patient＇ s parents or the controls. No mutation was found in KRT16 gene. Conclusion： A deletion mutation, N172del, has been found in a sporadic Chinese patient with PC- I. The mutation is not inherited from his parents, rather than a de novo mutation.