Prevalence and molecular characterization of alpha and beta-Thalassemia mutations among Hakka people in southern China

Our aim was to investigate molecular features of thalassemia for proper clinical consultation and prevention in Heyuan. In our research, a total of 25,437 positive screening subjects were further subjected to a genetic analysis of a-thalassemia (alpha-thal) and beta-thalassemia (beta-thal). The deletion of alpha-thal mutation was tested by Gap-PCR, while the non-deletion of alpha-thal and beta-thal mutation were identified by the PCR-reverse dot blot (PCR-RDB) technique. Nested PCR detected Hkaa/-- (SEA) and Hk alpha alpha/alpha alpha. Among the 25,437 positive screening subjects, 44.09% (11216/25437) subjects were bearers of thalassemia variations, and 30.85% (7847/25437) subjects showed alpha-thal changes alone. Among the 23 genotypes with alpha-thal mutation alone, the three common genotypes were --(SEA)/alpha alpha(68.34%), -alpha(3.7)/alpha alpha (16.44%), and -alpha(4.2)/alpha alpha(6.38%). Of the 11.50% (2924/25437) subjects and 29 genotypes with beta-thal mutation alone, the three common genotypes were beta(CD41-42)/beta(N)(36.22%), beta(IVS-II-654)/beta(N)(30.88%), and beta(-28)/beta(N)(13.47%). Additionally, of the 1.75% (445/25437) subjects and 55 genotypes showed both alpha- and beta-thal mutations. We also identified 269 cases of Hb H and six patients of Hk alpha alpha. Furthermore, the common genotypes of alpha-thal and beta-thal mutations were consistent with allele frequencies of mutations. Our study establishes molecular features of thalassemia among Hakka people in Heyuan. It will be useful for developing strategies to prevent thalassemia.