深圳地区小儿α和β地中海贫血基因类型分析

Genotype analysis of α-thalassemia and β-thalassemia in child patients of Shenzhen region

目的分析深圳地区小儿地中海贫血的基因类型及突变频率,为该疾病基因诊断及遗传咨询提供参考。方法回顾性分析1 206例疑似地中海贫血患儿,采用跨越断裂点PCR(Gap-PCR)检测缺失型α地中海贫血,反向点杂交(RDB)技术检测α和β地中海贫血基因点突变,巢式PCR检测疑似HKαα的样本并用基因测序验证疑似罕见地中海贫血的样本。结果1 206例病例中共检出927例地中海贫血(76.9%),其中489例(40.5%)α地中海贫血,主要以--SEA/αα为主(与75.1%);406例(33.7%)β地中海贫血,主要以IVS-2-654杂合子和CD41-42杂合子为主(分别占35%和32.5%)。检出αβ复合型地中海贫血32例(2.7%)。此外,发现HKαα/ααQS、α-地中海贫血突变基因类型CD61(AAG→TAG)/--SEA、β地中海贫血基因突变类型CD5(CCT→C)各1例。结论深圳地区地中海贫血患儿基因突变类型复杂多样,且存在多例罕见病例。

Objective To investigate the genotype and mutation frequency of thalassemia in child patients of Shenzhen region so as to provide evidences for the gene diagnosis and genetic counseling of thalassemia. Methods A total of 1 206 child patients suspected with thalassemia were retrospectively analyzed. The gene deletion of α-thalassemia was detected by Gap-PCR. The point mutations of α-thalassemia and β-thalassemia were determined by reverse dot blot（ RDB）-PCR. The specimens suspected with HKαα and rare gene mutations were determined with nested PCR and gene sequencing,respectively. Results The detection rate of thalassemia was 76. 9%（ 927/1 206）. Among them,α-thalassemia accounted for 40. 5%（ 489/1 206）,and--SEA/αα was the most common gene mutation（ 75. 1%）;β-thalassemia accounted for 33. 7%（ 406/1 206）,and the main IVS-2-654（ C→T） and CD41-42（-TCTT） heterozygous mutations accounted for 35% and 32. 5%,respectively. In addition,there were 32（ 2. 7%） β-thalassemia patients with α-thalassemia mutation,1patient with HKαα/ααQS,1 α-thalassemia patient with CD61（ AAG→TAG）/--SEA and 1 β-thalassemia patient with CD5（ CCT→C）.Conclusion The are complicated gene mutation types and rare gene mutations of thalassemia in child patients of Shenzhen region.