Molecular characterization of α- and β-thalassemia in the Yulin region of Southern China.

Thalassemia is one of the most common hereditary blood disorders. Epidemiological data regarding the prevalence and distribution of mutations is important for planning a thalassemia control program. To reveal the prevalence of thalassemia and mutation spectrum in the Yulin region of southern China, we screened 130,318 individuals from Yulin region by hematological and genetic analysis. Totally, 24,886 (19.10%) subjects were diagnosed with thalassemia, including 16,308 (12.51%) subjects with α-thalassemia alone, 6658 (5.11%) subjects with β-thalassemia alone and 1920 (1.47%) subjects with both α- and β-thalassemia. Ten α-thalassemia mutations were identified in the α-thalassemia subjects, with the common α-thalassemia mutations being --SEA mutation (51.91%), -α3.7 (19.90%), αCSα (10.58%), -α4.2 (8.13%), αWSα (7.67%). Thirteen β-thalassemia mutations and 31 genotypes were characterized in the β-thalassemia subjects. The seven common mutations [CD41-42 (-CTTT) (43.31%), CD17 (A > T) (34.58%), CD26 (G > A) (6.86%), CD71-72 (+A) (4.25%), -28 (A > G) (3.90%), IVS-II-654 (C > T) (3.53%) and IVS-I-1 (G > T) (2.22%)] accounted for 98.65% of all β-thalassemia defects. Furthermore, 6 cases of α-triplication and 3 cases of mutation -α2.4 were first identified in this region. Our data illustrated that there was great heterogeneity and extensive spectrum of thalassemias in the Yulin populations. The findings will contribute an available reference for prevention of thalassemia in this region.