青海地区苯丙酮尿症患者苯丙氨酸羟化酶基因突变分析

Mutation analysis of the PAH gene in children with phenylketonuria from the Qinghai area of China

摘要:

目的 明确青海地区苯丙酮尿症患者苯丙氨酸羟化酶(PAH)基因的突变特征,为该地区苯丙酮尿症(PKU)的产前诊断和遗传咨询提供理论依据。方法 选取2006年1月至2012年12月经新生儿疾病筛查及门诊遗传咨询发现并确诊的49例青海地区PKU患儿为研究对象,应用PCR产物直接测序法对49例PKU患儿及其父母的PAH基因启动子、第1~13外显子及其旁侧内含子区域进行基因突变分析。结果 在98个PAH等位基因中检测出30种、共计80个不同的突变基因,总检出率为82%(80/98),主要包括19种错义突变(63%)、5种无义突变(17%)、3种剪切位点突变(10%)和3种缺失突变(10%),大部分突变集中在第3、6、7、11外显子及第4内含子区域,常见的4种突变是p.R243Q(19%)、IVS4-1G>A(9%)、p.Y356X(7%)和p.EX6-96A>G(5%);p.N93fsX5(c.279-282delCATC)、p.G171E(c.512G>A)突变是国际上未见报道的新的PAH基因突变,p.H64fsX9(c.190delC)突变为国内第2次报道。青海地区PAH基因的突变构成有一部分与北方各省份相似,与中国南方部分省区及日本、欧洲等国家差异显著。结论 青海地区表现出多民族聚居地区PAH基因突变特有的多样性和复杂性。

Abstract:

Objective To study the mutation characteristics of the phenylalanine hydroxylase (PAH) gene in children with phenylketonuria (PKU) from the Qinghai area of China, in order to provide basic information for genetic counseling and prenatal diagnosis. Methods Mutations of the PAH gene were detected in the promoter and exons 1-13 and their flanking intronic sequences of PAH gene by PCR and DNA sequencing in 49 children with PKU and their parents from the Qinghai area of China. Results A total of 30 different mutations were detected in 80 out of 98 mutant alleles (82%), including 19 missense (63%), 5 nonsense (17%), 3 splice-site (10%) and 3 deletions (10%). Most mutations were detected in exons 3, 6, 7, 11 and intron 4 of PAH gene. The most frequent mutations were p.R243Q (19%), IVS4-1G>A (9%), p.Y356X (7%) and p.EX6-96A>G(5%). Two novel mutations p.N93fsX5 (c.279-282delCATC) and p.G171E (c.512G>A) were found. p.H64fsX9(c.190delC) was documented for the second time in Chinese PAH gene. The mutation spectrum of the gene PAH in the Qinghai population was similar to that in other populations in North China while significantly different from that in the populations from some provinces in southern China, Japan and Europe. Conclusions The mutations of PAH gene in the Qinghai area of China demonstrate a unique diversity, complexity and specificity.