Genotypes and phenotypes of rare thalassemia in Foshan, Guangdong Province / 中华地方病学杂志

ABSTRACT

Objective:To analyze the gene mutation types and haematological characteristics of αβ compound thalassemia, non-delectable α-thalassemia and Hemoglobin H Disease (HbH disease) in Foshan.Methods:Using the method of retrospective analysis, we selected the population who had been tested for thalassemia gene in Foshan Second People's Hospital Affiliated to Southern Medical University from January 2011 to November 2019. Sysmex XT-5000 automatic hematology analyzer was used for routine blood analysis. α-, β- thalassemia genes were detected by PCR + diversion hybridization method.Results:A total of 4 563 people were tested, of which 1 829 were diagnosed as thalassaemia through genetic diagnosis. αβ compound thalassaemia was detected in 81 cases with a positive rate of 1.8%; non-delectable α-thalassemia was detected in 18 cases with a positive rate of 0.4%; HbH disease was detected in 23 cases with a positive rate of 0.5%. The most common genotypes of αβ compound thalassemia were -- SEA/αα\β41-42/βN (17.3%, 14/81), -α 3.7/αα\β41-42/βN (14.8%, 12/81), -- SEA/αα\β654/βN (11.1%, 9/81). The main manifestations of hematology were normal to mild anemia (93.8%, 76/81). Only β-thalassemia with double heterozygotes and α-thalassemia showed severe anemia. αα CS/αα\βN/βN genotypes were common in the local non delectable α-thalassemia (50.0%, 9/18), and the non delectable α-thalassemia was characterized by non-positive phenotype or typical small-cell hypochromatosis in hematology. The genotypes of local HbH patients were -α 3.7/-- SEA\βN/βN (65.2%, 15/23), and simple HbH manifested as moderate anemia (87.0%, 20/23). Patients with HbH disease and β-thalassemia had normal or mild anemia (13.0%, 3/23). Conclusions:The genotypes of αβ compound thalassemia in Foshan area are diverse and complex, and hematology mainly manifests as mild anemia or normal. Non-delectable α-thalassaemia is common in the genotype of αα CS/αα\βN/βN, and clinical manifestations are asymptomatic gene carriers. The genotype of local HbH patients is mainly -α 3.7/-- SEA\βN/βN, and the hematology mainly shows moderate anemia.