Investigation of rare hemoglobin-coding gene defects among Chinese population

Abstract

Objective To summarize the types of rare hemoglobin-coding gene defects and their phenotypes in Chinese population, aimed at providing reference for genetic counseling of couples in childbearing age from areas with high prevalence of thalassemia. Methods By investigating the literature at home and abroad on the prevalence and phenotypes of thalassemia published between 2011 and 2021, and combining with four rare thalassemia mutant genes discovered in our clinical work, the types of rare hemoglobin-coding gene defects in China were summarized, and the characteristics and phenotypes were outlined through International Human Abnormal Hemoglobin Database. Results Aside from 23 common thalassemia genes, rare hemoglobin-coding gene defects have been detected in 11 provinces in southern China. Of the 109 rare α alleles, 41 alleles (including 9 hemoglobin variants) had been identified to cause α-thalassemia, 39 hemoglobin variants, 2 copy number repeats, 5 single nucleotide polymorphism, and 22 new point mutation with unclear function. Of the 160 rare β alleles, 89 alleles had been identified to cause β-thalassemia, 41 hemoglobin variants, 6 single nucleotide polymorphism, and 24 new point mutation with unclear function. Conclusion This study, based on the discovery of rare thalassemia gene in clinical work, explored the types of rare hemoglobin-coding gene defects and their phenotypes in Chinese population in recent years and provided reference for genetic counseling of thalassemia.

Keywords

• thalassemia
• rare genotype
• hemoglobin
• hematologic phenotype