四川地区重型β-地中海贫血患儿及双亲基因突变的研究

Genetic Study on 27 Children with β-thalassemia Major and Their Parents in Sichuan Area

目的 探讨四川地区重型 β-地中海贫血患儿及其双亲突变基因类型的特点。方法 对 2 7例 β-地中海贫血患儿及双亲采用盐水渗透性试验测定红细胞渗透脆性、碱变性法测定抗碱血红蛋白 (Hb F)、醋酸纤维薄膜电泳比色法测定血红蛋白 A2 (Hb A2 )和氰化高铁血红蛋白法测定 Hb等 β-地中海贫血血液学检查。用常规方法抽提外周血白细胞 DNA,多重等位基因特异聚合酶链反应 (MASPCR)分析其基因类型。结果 2 7例重型 β-地中海贫血患儿及其双亲共 81例标本中检测出最常见的 3种基因突变是 CDl7(A→ T)、CD4 1- 4 2 (- TTCT)、IVS- - 6 5 4(C→ T) ,占总数的 94 .5 4 %。结论 采用 MASPCR法进行基因诊断 ,具有操作简单、快速准确 ,一次可检测多种突变基因型 ,提高了基因诊断率。

Objective This genetic analysis on 27 children with β-thalassemia major and their parents was performed in an attempt to elucidate the characteristics of gene mutations, and to improve the early diagnosis and prevention of this disease in Sichuan area. Methods The hematologic studies of β-thalassemia included the osmotic fragility of erythrocyte determined by brine osmosis method, the HbF qualitatively determined by one minute anti-alkaline method, the HbA 2 assayed by acetyl-cellulose membrane electrophoresis and eluate photometric method, and the total hemoglobin measured by the ferric-cynade method. DNA was extracted from peripheral white blood cell with standard method (phenol-chloroform extract). Multiple allele specific polymerase chain reaction (MASPCR) was used for targeted DNA amplification and gene mutation analysis. Results It was found that the most common mutants in Sichuan area were CD17(A→T), CD41-42(-TTCT) and IVSⅡ-654(C→T). Their percentages were 43.64%, 36.36% and 14.54%, respectively. Conclusion MASPCR method is a simple, effective and inexpensive method for genetic diagnosis of β-thalassemia major. We identified 3 most common mutants in Sichuan by using MASPCR.