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

• Published in: Hematology (Luxembourg) Vol. 27; no. 1; pp. 826 - 830
• Main Authors: Bao, Xiuqin, Wang, Jicheng, Qin, Danqing, Zhang, Rui, Yao, Cuize, Liang, Jie, Liang, Kailing, Du, Li
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 31.12.2022; Taylor & Francis Group
• Subjects: 3.7; 3.7 III; Chinese population; microcytosis and hypochromic red cells; single molecule real time sequencing; subtypes; α3.7 III; α3.7 subtypes
• ISSN: 1607-8454; 1607-8454
• DOI: 10.1080/16078454.2022.2101913

The 3.7 kb deletion (-α 3.7 ) in the α-globin cluster, which characterizes α + -thalassemia, has been reported to have a carrier rate of 4.78% in southern China. Three -α 3.7 subtypes have been identified worldwide. However, the -α 3.7 III subtype has not previously been identified in China. Herein, we reported identification of the -α 3.7 III subtype in a Chinese patient. 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. The proband, characterized as -α 3.7 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. We first identified the -α 3.7 III subtype in China. Consequently, all -α 3.7 subtypes have now been identified in the Chinese population. Therefore, attention should be paid to -α 3.7 III in clinical prenatal diagnosis, given that commonly used methods such as gap-PCR may lead to misdiagnosis or missed diagnosis.