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

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。

Detection of alpha-thalassemia 1 gene among 142 beta-thalassemia gene carriers]

OBJECTIVE: To investigate the coincidental rate of double heterozygous state of beta-thalassemia and alpha-thalassemia 1 in Guangdong area. METHODS: One handred and forty-two DNA samples with beta-thalassemia trait were amplified by polymerase chain reaction(PCR) to detect alpha-thalassemia 1 gene. The positive cases were further detected by mutant primer PCR or by reverse dot blot hybridization (ASO/RDB) to confirm their beta-thalassmia mutations. RESULTS: Thirteen cases (9.15%) were identified to combine with alpha-thalassemia 1 gene. The mutant loci of beta-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 beta-thalassemia trait is relatively frequent and it should be paid much attention to in genetic counselling and prenatal diagnosis of thalassemia in this area.