对142例β地中海贫血基因携带者进行缺失型α地中海贫血1基因分析

Detection of α thalassemia 1 gene among 142 β thalassemia gene carriers

目的了解广东地区常见的β地中海贫血（地贫）与α地贫１复合存在的发生率。方法应用聚合酶链反应（ＰＣＲ）技术对１４２例经筛查确定为轻型β地贫的成人血样ＤＮＡ进行α地贫１基因检测，阳性者又应用突变引物ＰＣＲ特异扩增或用等位基因特异寡核苷酸探针反向点杂交（ＡＳＯ／ＲＤＢ）技术，确定其β地贫基因突变类型。结果１４２例中有１３例轻型β地贫样本同时合并有α地贫１基因，占总数的９１５％，其β地贫基因的突变类型分别是：ＣＤ４１４２（－ＴＣＴＴ）突变５例，ＩＶＳ２６５４（Ｃ→Ｔ）突变３例，ＣＤ１７（Ａ→Ｔ）突变２例，ＣＤ７１７２（＋Ａ）、ＣＤ４３（Ｇ→Ｔ）和－２８（Ａ→Ｇ）突变各１例。结论β地贫复合α地贫１的双重杂合子在轻型β地贫个体中的发生率较高，是该地区在地贫的遗传咨询和产前诊断工作中值得重视的一个问题。

Objective To investigate the coincidental rate of double heterozygous state of β thalassemia and α thalassemia 1 in Guangdong area.Methods One hundred and forty two DNA samples with β thalassemia trait were amplified by polymerase chain reaction(PCR) to detect α thalassemia 1 gene.The positive cases were further detected by mutant primer PCR or by reverse dot blot hybridization (ASO/RDB) to confirm their β thalassmia mutations.Results Thirteen cases (9 15%) were identified to combine with α thalassemia 1 gene.The mutant loci of β globin gene in these cases were that 5 were in CD 41 42 (-TCTT), 3 in IVS 2 654(C→T),2 in CD 17 (A→T) and 3 in CD 71 72 (+A),CD 43(G→T) and -28(A→G),respectively.Conclusions The occurrence of this dual heterozygotes among β thalassemia trait is relatively frequent and it should be paid much attention to in genetic counselling and prenatal diagnosis of thalassemia in this area.