The carriage rates of αααanti3.7, αααanti4.2, and HKαα in the population of Guangxi, China measured using a rapid detection qPCR system to determine CNV in the α-globin gene cluster

Our study group encountered a pregnant woman whose gene analysis of thalassemia was β41-42/βN; however, the patient was severely anemic and had a history of multiple blood transfusions. Further analysis showed that the individual carried the αααanti4.2. Our research group occasionally detected individuals with copy number variations of the α gene, including αααanti3.7, αααanti4.2, and HKαα, but these variations are not within the detection range of conventional gene detection for thalassemia. The purpose of this study was to determine the carriage rate of these α gene copy number variants in the population of southern Guangxi. We used the method of relative quantitative homologous fragments to analyze α1 and α2 genes. 23,900 samples were analyzed. A total of 201 individuals with αααanti3.7, αααanti4.2, and HKαα genes were identified. The carriage rates of these genes in southern Guangxi were 0.39%, 0.29% and 0.16%, respectively. We also collected positive samples from 18 families, and hematology data analysis confirmed that if these individuals carried the β-thalassemia allele at the same time, would lead to further imbalance of the ratio of α-chain to β-chain, and then produce varying degrees of anemia. The individuals carrying αααanti3.7, αααanti4.2, and HKαα genes suffer harms related to β0 thalassemia, and these variations are not included in the detection range of conventional gene analysis reagents; therefore, these individuals are at risk. Prenatal diagnosis institutions could pay more attention to carriage of copy number variations of α-globin, so as to give more accurate prenatal advice to patients.