Abstract:

Objective To analyze the genotype distribution and hemoglobin（Hb）A₂ parameter characteristic in thalassemia carriers or patients. Methods The genotype distribution of 2 194 α-thalassemia and 970 β-thalassemia female carriers or patients was analyzed retrospectively,and the HbA₂ levels of 1 438 α-thalassemia and 646 β-thalassemia carriers or patients were also analyzed. A total of 1 629 healthy females without thalassemia were enrolled as control group. Results The α-thalassemia group included silent group（740 cases）,trait group（1 400 cases） and HbH disease group（54 cases）. There were 5 genotypes in silent group,and -α^3.7/αα and -α^4.2/αα were common. There were 9 genotypes in trait group,and --^SEA/αα was common. There were 5 genotypes in HbH disease group,and -α^3.7/--^SEA was common. There was no statistical significance for HbA₂ levels between control and silent groups（P>0.05）,and the levels of HbA₂ were decreased in turn in control,silent,trait and HbH disease groups（P<0.05）. The β-thalassemia group included β^E-thalassemia group（26 cases）,β⁺-thalassemia group（400 cases） and β⁰-thalassemia group（544 cases）. Just 1 genotype was identified in β^E-thalassemia group,which was β^CD26/β^N. Four genotypes were identified in β⁺-thalassemia group,of which β^IVS-Ⅱ-654/β^N and β^-28/β^N were common. Eight genotypes were identified in β⁰-thalassemia group,of which β^CD41-42/β^N and β^CD17/β^N were common. HbA₂ levels were increased in the order of control,β⁺-thalassemia,β⁰-thalassemia and β^E-thalassemia groups（P<0.05）. Conclusions HbA₂ is important for β-thalassemia and HbH disease screening,and the results of blood routine test should be also considered in genetic counseling in case of silent and trait α-thalassemia being ignored.

Key words: Thalassemia, Genotype, Hemoglobin