Genetic epidemiology of thalassemia in couples of childbearing age: over 6 years of a thalassemia intervention project

Background Shenzhen is one of the most populated metropolises in southern China where thalassemia is highly prevalent. The prevention of thalassemia inheritance is an ambition of child-bearing couples. Methods and results A total of 22,098 peripheral blood samples were collected from 11,049 potentially at-risk couples of childbearing age from Shenzhen. Thalassemia mutations were determined by PCR-based flow-through hybridization. The results identified 45.02% of the participants (9948 out of 22,098) as harboring globin gene mutations, distributed into 18 α-thalassemia alleles detected in 71.48% (7111 out of 9948) and 15 β-thalassemia alleles detected in 32.68% (3252 out of 9948) of all mutant individuals, among which 415 individuals carried both α- and β-thalassemia alleles. The most frequent phenotypes for α-globin variations were -- SEA /αα (63.37%), -α 3.7 /αα (18.66%), and -α 4.2 /αα (7.31%), and those for β-globin variations were β 41–42 /β N (34.96%), β 654 /β N (28.11%), and β 17 /β N (13.84%). A total of 970 high-risk couples who could possibly give birth to offspring with thalassemia intermedia or major were identified. In addition, the hematological indices were compared among thalassemia genotypes. Significant differences in MCH, MCV, Hb A, and Hb A2 levels among α-thalassemia minor (α+), trait (α0), and intermediate phenotypes ( P