Objective: To perform genetic analysis, prenatal diagnosis and preimplantation genetic diagnosis (PGD) in a family with a rare deletional β- thalassemia.
Methods: Hematological parameters of the peripheral blood collected from all the family members were analyzed by whole blood cell analysis and capillary zone electrophoresis (CZE). Polymerase chain reaction-reverse dot blot (PCR-RDB) was used to identify 17 common β- thalassemia gene mutations, the multiplex ligation-dependent probe amplification (MLPA) and gap-polymerase chain reaction (gap-PCR) were used to identify β- globin gene cluster deletions. Chorionic villus sample or umbilical cord blood was obtained for prenatal diagnosis. Oligo-cells from blastocyst biopsy were collected for preimplantation genetic diagnosis by whole genome amplification and next generation sequencing.
Results: The proband was a carrier of Taiwanese deletion β- thalassemia, two fetuses were both thalassemia majors. The PGD results showed that 6 of 11 tested embryos could be choose for transplantation.
Conclusion: The Taiwanese deletion is a rare type deletion of β- globin gene cluster, and it can lead to thalassemia intermedia or thalassemia major when compounded with other β- globin gene mutation. PGD is another choice for thalassemia couples.
题目: 台湾型缺失β地中海贫血的基因诊断、产前诊断和植入前遗传学诊断.
目的: 对1个罕见缺失型β地中海贫血家系进行基因诊断、产前诊断和胚胎植入前遗传学诊断及分析.
方法: 采用血常规和血红蛋白电泳分析家系中所有成员外周血的血液学指标，采用聚合酶链反应结合反向点杂交（PCR-RDB）、多重连接探针扩增技术（MLPA）及裂隙聚合酶链反应（gap-PCR）方法进行β地中海贫血基因诊断，采集脐带血或者绒毛膜组织进行产前诊断。囊胚活检滋养外胚层细胞经过全基因组扩增后利用第二代测序技术单体型构建进行胚胎植入前遗传学诊断.
结果: 基因诊断检测出该家系的先证者为罕见的台湾型缺失β地中海贫血携带者。2次产前诊断结果显示，2个胎儿均为重型β地中海贫血患者。植入前遗传学诊断发现在11个胚胎中检测出6个可供移植胚胎.
结论: 台湾型缺失是罕见的β地中海贫血缺失类型，当复合β珠蛋白基因其他突变时可导致中重型β地中海贫血。胚胎植入前遗传学诊断是可供地中海贫血高风险家庭选择的一种优生方式.