Accurately Detection of A-Globin Gene Copy Number Variants With Two Reactions Using Droplet Digital PCR

Abstract Background: α-thalassemia, with carrier rates of 11.31% and 17.55% respectively in Guangdong and Guangxi province, is a highly prevalent disease in Southern China and tropical and subtropical regions and is mainly caused by deletion in α-globin gene (HBA1 and HBA2). The clinical manifestation of α-thalassemia is highly correlated with the copy number of α-globin gene. The decrease of copy number results in α-thalassemia, while duplication or triplication compounded with β-thalassemia may aggravate the clinical manifestation. However, the usual methods we used to measure the copy number variants can only detect the three common types: --SEA, -α3.7 and − α4.2, which may easily miss the rare deletional type and duplication or triplication cases. Therefore, it is essential to establish a new method which allows detection of different copy number variants in α-globin genes, including deletion, duplication and triplication simultaneously and accurately.Methods: 428 peripheral blood and fetal chorionic villus or amniotic fluid samples were recruited in this study. We used a pair of primers and two probes to perform droplet digital PCR.Results: By performing only two reactions, we accurately detected the copy number variants in α-globin genes, including the common form α-thalassemia, triplications such as αααanti4.2 and trisomy 16. The accuracy rate for detecting the copy number of α-globin genes can up to 100%.Conclusions: In conclusion, droplet digital PCR served as an accurate and rapid method for copy number variation detection in clinical screening for α-thalassemia.