The -α3.7III subtype of α+-thalassemia was identified in China

Abstract

ABSTRACT Objective The 3.7 kb deletion (-α3.7) in the α-globin cluster, which characterizes α+-thalassemia, has been reported to have a carrier rate of 4.78% in southern China. Three -α3.7 subtypes have been identified worldwide. However, the -α3.7 III subtype has not previously been identified in China. Herein, we reported identification of the -α3.7 III subtype in a Chinese patient. Methods We used gap-PCR and a liquid chip system to detect α-thalassemia mutations. Multiple ligation-dependent probe amplification was performed to detect the large deletion. We finally used Sanger sequencing and single molecule real-time sequencing to characterize and confirm the genotype. Results The proband, characterized as -α3.7 III heterozygous, showed microcytosis and hypochromic red cells, with a mean corpuscular volume of 78 fL and mean corpuscular hemoglobin of 25.4 pg. The proband’s mutation was inherited from her father, who had normal blood parameters. Conclusion We first identified the -α3.7 III subtype in China. Consequently, all -α3.7 subtypes have now been identified in the Chinese population. Therefore, attention should be paid to -α3.7 III in clinical prenatal diagnosis, given that commonly used methods such as gap-PCR may lead to misdiagnosis or missed diagnosis.