Genetic variation and distribution characteristics of thalassemia in people of childbearing age in Hubei Province / 中华地方病学杂志

ABSTRACT

Objective:To study the genetic variation and distribution characteristics of thalassemia in people of childbearing age in Hubei Province, and to provide clinical basis for the local government decision-making departments to formulate and promote appropriate policies for prevention and control of thalassemia.Methods:Venous blood samples were collected from 44 849 people of childbearing age in hospitals in Hubei Province from May 13, 2019 to August 17, 2021. PCR-flow fluorescence hybridization and PCR+diversion hybridization were used to screen thalassemia genes. Spouses of those who tested positive were also tested for thalassemia genes. When both spouses carried the same type of thalassemia gene, the amniotic fluid of pregnant women was extracted for prenatal diagnosis and followed up.Results:Among the 44 849 people of childbearing age, 2 286 cases were diagnosed as thalassemia gene carriers through genetic testing, and the total detection rate was 5.10% (2 286/44 849). Among them, 1 488 cases were diagnosed as α-thalassemia, and the detection rate was 3.32% (1 488/44 849); 767 cases were diagnosed as β-thalassemia, and the detection rate was 1.71% (767/44 849); 31 cases were diagnosed as α-thalassemia combined with β-thalassemia, and the detection rate was 0.07% (31/44 849). The top three genotypes of α-thalassemia were -α 3.7/αα, -- SEA/αα, and -α 4.2/αα, accounting for 58.06% (864/1 488), 26.14% (389/1 488), and8.74% (130/1 488), respectively. The top three genotypes of β-thalassemia were β IVS-Ⅱ-654/β N, β CD41-42/β N, and β CD17/β N, accounting for 41.72% (320/767), 21.25% (163/767), and 16.04% (123/767), respectively. The main genotypes of α-thalassemia combined with β-thalassemia were -α 3.7/αα complex β IVS-Ⅱ-654/β N and -α 3.7/αα complex β CD41-42/β N, accounting for 29.03% (9/31) and 16.13% (5/31), respectively. A total of 59 people of childbearing age were conducted prenatal diagnosis, among fetus, there were 4 cases of severe thalassemia (2 cases of severe α-thalassemia, 2 cases of severe β-thalassemia), 5 cases of intermediate α-thalassemia, 5 cases of intermediate or severe β-thalassemia, 19 cases of mild thalassemia (8 cases of mild α-thalassemia, 11 cases of mild β-thalassemia), 13 cases of stationary α-thalassemia, and 1 case of stationary α-thalassemia combined with mild β-thalassemia, there were 12 cases without α-thalassemia or β-thalassemia genes. After follow-up, 4 cases of severe thalassemia, 2 cases of intermediate α-thalassemia, and 5 cases of intermediate or severe β-thalassemia were terminated pregnancy by the joint decision of both parents. Conclusions:In Hubei Province, the detection rate of thalassemia is high, and α-thalassemia is the main mutation type. The combination of thalassemia gene screening and prenatal diagnosis is of great significance in reducing the birth rate of children with thalassemia.