一种新的G6PD基因突变型的鉴定

目的:鉴定1例葡萄糖-6-磷酸脱氢酶缺乏症患者的基因突变。方法:用聚合酶链反应、限制性内切酶筛查葡萄糖-6-磷酸酶基因1388G→A、1376G→T、1360C→T、1024C→T、592C→T、517T→C、493A→G,487G→A、392G→T、95A→G突变,用单链构象多态性筛查葡萄糖-6-磷酸脱氢酶基因的所有外显子,用核苷酸序列测定确定基因突变。结果:该患者未存在1388G→A、1376G→T、1360C→T、1024C→T、592C→T、517T→C、493A→G、487G→A、392G→T、95A→G突变,但在外显子8发现了一种新的G6PD基因突变———835A→G突变,此突变导致第279位的苏氨酸被丙氨酸取代,将其命名为G6PD-海口,其酶活性约是正常的10%,比835A→T突变型的活性低,后者的酶活性约是正常的40%;分析人G6PD的三维结构模型表明,第279位苏氨酸残基的羟基对于维持G6PD亚基的相互作用具有非常重要的作用。结论:835A→G突变是一种新的G6PD基因突变型,G6PD的第279位苏氨酸残基的羟基是维持G6PD亚基相互作用及酶活性的必需基团。

IDENTIFICATION OF A NOVEL MUTATION IN HUMAN G6PD GENE

Objective:To identify the mutation of glucose-6-phosphate dehydrogenase gene in a G6PD deficient case.Method:Polymerase chain reaction,restriction enzyme digestion were used to screen the known mutations1388G→A,1376G→T,1360C→T,1024C→T,592C→T,517T→C,493A→G,487G→A,392G→T and95A→G in human G6PD gene.Single strand conformation polymorphism analysis was used to screen all the exons of G6PD gene.DNA sequencing was used to determine the mutations.Results:The known mutations1388G→A,1376G→T,1360C→T,1024C→T,592C→T,517T→C,493A→G,487G→A,392G→T and95A→G were not found in the case.A novel mutation835A→G in exon8of G6PD gene was found.The mutation causes the substitution of Ala for Thr at279and was named as G6PD-Haikou.The enzyme activity of the variant is about 10%of the normal and lower than the activity of the variant 835A→T with about 40%of the normal.Analysis of the3D model of human G6PD revealed the importance of hydroxyl group of Thr at279in maintaining the interaction of the G6PD subunits.Conclusion:The835A→G tromsition is a novel mutation.the hydroxyl group of the Thr at279of human G6PD is a necessary group for maintaining the interaction of the G6PD subunits and the enzyme activity.