Prevalence and genetic analysis of α- and β-thalassemia in Baise region, a multi-ethnic region in southern China.

Thalassemia is one of the most common hereditary blood disorders. Epidemiological data regarding the occurrence and distribution of thalassemia is important for designing appropriate prevention strategies. The objective of this study was to update and reveal the prevalence of thalassemia and mutation spectrum in the Baise region of southern China. We screened 47,500 individuals from Baise region by hematological and genetic analysis. Totally, 11,432 (24.07%) subjects were diagnosed as being carriers and patients of thalassemia, including 7290 (15.35%) subjects with α-thalassemia, 3152 (6.64%) subjects with β-thalassemia and 990 (2.08%) subjects with both α-thalassemia and β-thalassemia. Ten α-thalassemia mutations and 31 genotypes were identified in the α-thalassemia carriers and patients. Meanwhile, 13 β-thalassemia mutations and 26 genotypes were characterized in the β-thalassemia carriers and patients. Furthermore, the true prevalence of nondeletional mutations and Thailand type (-THAI) deletion mutation were first reported in this study. In addition, three cases of αα/ααα3.7, five cases of HKαα/αα and two rare β-globin mutations, -86 (G>C) and CD 121 (G>T) were first identified in the Chinese Zhuang ethnic populations. Our data indicated that there was great heterogeneity and extensive spectrum of thalassemias in the Baise populations. The findings will be useful for genetic counseling and prevention of severe thalassemia in this region.