Abstract: Objective To analyze 2 families with rare thalassemia and make prenatal diagnosis thalassemia. Methods The family members' peripheral blood samples were analyzed by whole blood cell analysis and hemoglobin analysis with capillary zone electrophoresis.Conventional α and β thalassemia genes were detected by flow-through hybridization for peripheral blood samples and amniotic fluid samples.Multi-Link Probe Amplification Technology(MLPA),DNA sequencing,gap PCR (Gap-PCR) and continuous electrophoresis of hemoglobin were used to analyze the rare genotypes. Results A case of rare type of β-thalassemia with Vietnamese deletion and a case of sea deletion compound of α2 gene CD124 mutation were detected in 2 families.To prenatal diagnosis among 2 families,one of the fetuses was detected for β-thalassemia with Vietnamese deletion,another was α thalassemia with sea deletion. Conclusions When the Results of hematological phenotype and genotype do not match,much attention should be paid to further detection of rare genotypes to avoid missed diagnosis or misdiagnosis,especially to the couples who have had children with severe thalassemia.The finding may enrich knowledge of the screening in thalassemia as well as the genetic counseling and clinical diagnosis.

Key words: rare genotype, thalassemia, prenatal diagnosis

摘要： 目的 对2例罕见地中海贫血(地贫)家系进行分析及产前诊断。方法 采集家系成员外周血进行血细胞分析及毛细管电泳血红蛋白分析;采集外周血及羊水,用导流杂交法进行常规α和β地中海贫血基因检测;采用多重链接探针扩增技术(MLPA)、DNA测序、缺口PCR(Gap-PCR)技术及血红蛋白持续增多症缺失型电泳等技术分析其罕见基因型。结果 在2个家系中检测到1例罕见的越南型缺失β地中海贫血及1例东南亚缺失型α地贫复合α2基因CD124点突变;并对2个家系进行了产前诊断,检测到1个胎儿为越南型缺失β地中海贫血,另一个为东南亚缺失型α地贫。结论 当血液学表型与基因型不符时,应进一步做罕见基因型的检测以避免漏诊或误诊,特别是生育过重型地贫患儿的夫妇。这有助于指导临床诊断、人群筛查和遗传咨询。

关键词: 罕见基因型, 地中海贫血, 产前诊断