The Prevalence and Spectrum of α-Thalassemia in Guizhou Province of South China.

α-Thalassemia (α-thal) is one of the most prevalent genetic diseases in the world and is especially frequent in tropical and subtropical regions, including South China. The aim of this study was to investigate the prevalence and spectrum of α-thal in Guizhou Province as this information was unknown. A total of 40 α-thal carriers were determined in 1219 newborn umbilical cord blood samples by hemoglobin (Hb) electrophoresis combined with DNA analysis, which revealed that the carrier rate of α-thal in Guizhou Province was 3.28%. One thousand and forty-five individuals referred to our hospital were tested for α-thal mutations. Two hundred and twenty-four cases were determined as α-thal carriers or patients. A total of 11 genotypes and five different α-thal mutations were identified in these 224 cases. Of these mutations, more than 96.0% were deletions, including - -(SEA) (65.89%), -α(3.7) (rightward) (22.87%) and -α(4.2) (leftward) (7.74%). The other two nondeletional mutations, Hb Constant Spring (Hb CS, α(CS)α, HBA2: c.427T > C) and Hb Quong Sze [Hb QS, α(QS)α, HBA2: c.377T > C (or HBA1)] account for 2.71% and 0.78%, respectively. The results of this study will be useful in genetic counseling and prenatal diagnosis (PND) of α-thal in Guizhou Province.