Prevalence, genotype and hematological phenotype analysis of hemoglobinopathy in Chongqing

Abstract:

Objective To analyze the prevalence，genotype composition and hematological characteristics of hemoglobinopathy in Chongqing，and to reasonably select screening and diagnostic methods for hemoglobinopathy.Methods Peripheral blood samples were collected from 49 551 patients screened for hemoglobinopathy，and 23 common gene loci of thalassemia and mutations related to hemoglobin variants（HbVs） were detected by multiplex PCR-guided hybridization or sequencing. The results of routine blood test and hemoglobin electrophoresis were retrospectively analyzed to evaluate the value of the combined examination in the screening and diagnosis of hemoglobinopathy.Results A total of 3 511 cases of hemoglobinopathy were detected（7.09%）. Among them，there were 1 840 α-thalassemia and 1 540 cases of β-thalassemia gene carriers，respectively，mainly including --^SEA/αα，-α^3.7/αα，and -α^4.2/αα for α-thalassemia cases，and CD17，IVS-Ⅱ-654 and CD41-42 for β-thalassemia；there were 65 cases of abnormal hemoglobinopathy，with the majority of β-chain variants；there were 64 cases of complex hemoglobinopathy，including 57 cases of α-thalassemia combined with β-thalassemia and 7 cases of thalassemia combined with abnormal hemoglobinopathy. The decrease of hemoglobin，mean corpuscular volume and mean corpuscular hemoglobin in patients with hemoglobinopathy was positively correlated with the decrease of α or β chain synthesis，while adult hemoglobin 2（HbA2） was respectively decreased and increased in α-thalassemia and β-thalassemia，or there were HbVs in abnormal hemoglobiopathies. The detection rate of hemoglobinopathy was 84.29% and 82.67% by routine blood test and capillary electrophoresis，respectively，and the detection rate of combined screening was 99.11%.Conclusion The genotype of carriers of hemoglobinopathy in Chongqing area is diverse. Blood routine combined with Hb electrophoresis is a necessary means for clinical and prenatal screening of hemoglobinopathy. Follow-up genetic analysis is strongly recommended in patients screened for HbVs who present with symptoms such as hemolysis or anemia.