肾上腺皮质增生患者的常见突变是该疾病新发生突变的热点区域

Common mutations of congenital adrenal hyperplasia are also the hotspots for new mutations

目的对肾上腺皮质增生患者及家属(CAH)进行基因诊断并探讨其突变来源。方法通过限制性内切酶特异性识别突变位点的酶学方法对患者及其家系进行基因诊断。通过PCR测序的方法对收集到的家系进行DNA测序,分析确定肾上腺皮质增生致病基因21-羟化酶的突变。运用基因组短串联重复序列多态性(STR)分型技术进行亲缘关系分析,用以确定突变位点来源。结果患者(病例号7424)21-羟化酶基因存在I2g和I172N两个已知突变。I2g突变遗传自母亲(病例号7536),I172N系新发生突变。STR分析结果表明该患者的遗传物质一半来自母亲(病例号7536),一半来自父亲(病例号7535),二者系患者的生物学父母。结论肾上腺皮质增生疾病中出现的常见基因突变在遗传过程中也是新发生突变的热点区域。

Objective To discuss the genetic diagnosis of congenital adrenal hyperplasia（CAH） and investigate the resource of gene mutations in CAH.Method Enzymatic methods with restriction endonucleases that specifically recognized the mutation sites were used to detect the gene mutations in patients with CAH and their relatives.Polymerase chain reaction and direct sequencing were used to identify the mutations in 21-hydroxylase gene,and short tandem repeat（STR） typing was used to determine the sources of the mutations.Results One CAH patient had two known mutations in 21-hydroxylase gene,namely the I2g and I172N mutations.The former mutation was inherited from the biological mother and the latter was not inherited.Conclusion The 9 common mutations of CAH are also the hotspots for new mutations.