海南汉族、黎族人葡萄糖-6-磷酸脱氢酶缺乏症的基因突变型分析及一种新的G6PD基因突变型的鉴定

目的 阐明海南汉族、黎族人群中葡萄糖－6－磷酸脱氢酶缺乏症的分子基础。方法 用聚合酶链反应、限制性内切酶消化筛查了1388G→A、1360C→T、1024C→T、517T→C、493A→G、487G→A、392G→T和95A→G突变。用单链构象多态性分析筛查其它突变；用核苷酸顺序分析鉴定具有SSCP异常区带样品的突变；。结果 在59例汉族G6PD缺乏症患者中，发现1388G→A14例（23．7％）、871G→A3例（5．1％）、835A→T1例（1．7％）517T→C1例（1．7％）、392G→T3例（5．1％）95A→G4例（6．8％）；在32例黎族G6PD缺乏症患者中，发现1388G→A6例（18．8％）、871G→A3例（9．4％）和95A→G2例（6．3％）；在1例汉族患者中发现了一种新的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，将此突变型命名为G6PD－海口，其酶活性约是正常的10％，此835A→T突变的活性低，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是维持G6PD亚基相互作用的基团。结论 海南汉族、黎族人群中具有共同的常见G6PD基因突变型；与中国其它地区人群的G6PD基因突变谱比较，结果表明某些G6PD基因突变广泛分布于中国南方不同地区人群中；G6PD第279位苏氨酸残基的可能是维持G6PD亚基相互作用及酶活性的必需基团。

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in the Han and Li nationalities in Hainan, China and identification of a new mutation in human G6PD gene

OBJECTIVE: To elucidate the molecular basis of G6PD deficiency in the Han and Li nationalities in Hainan, China. METHODS: Polymerase chain reaction and restriction enzyme digestion were used to screen the mutations 1388G-->A, 1360C-->T, 1024C-->T, 592C-->T, 517T-->C, 493A-->G, 487G-->A, 392G-->T and 95A-->G. Single strand conformation polymorphism analysis was used to screen the other mutations followed by DNA sequencing to characterize the mutations of the samples with abnormal SSCP bands. RESULTS: Of the fifty-nine Han cases with G6PD deficiency, fourteen with 1388G-->A (23.7%), three with 871G-->A(5.1%), one with 835A-->T(1.7%), one with 517T-->C (1.7%), three with 392G-->T(5.1%), and four with 95A-->G(6.8%) were found. Of the thirty-two Li cases with G6PD deficiency, six with 1388G-->A(18.8%), three with 871G-->A(9.4%), and two with 95A-->G(6.3%) were found. A new mutation 835A-->G which causes the substitution of Ala for Thr at 279 in a Han case was identified and 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 the 3D model of human G6PD has revealed that the hydroxyl group of Thr at 279 is a group in maintaining the interaction of the G6PD subunits. CONCLUSION: The most common mutations of G6PD deficiency in Han and Li nationalities in Hainan are similar. Compared with the mutation spectrum of G6PD gene in the populations in other regions of China, the results indicate that some G6PD gene mutations are widespread in the populations of different regions in the southern part of China. The hydroxyl group of the Thr at 279 of human G6PD may be a necessary group for maintaining the interaction of the G6PD subunits and the enzyme activity.