RESUMO
Objective:A rare case of δ-globin gene (HBD) mutation in Guangdong Province was analyzed to provide reference for avoiding misdiagnosis of δ-thalassemia in clinic.Methods:The patient was admitted to Guangdong Maternal and Child Health Hospital, and the peripheral blood sample was collected for hematological phenotypes [mean erythrocyte volume (MCV), mean erythrocyte hemoglobin content (MCH), hemoglobin (Hb)] and Hb typing analysis. The routine deletion and mutation of α-thalassemia and β-thalassemia genes were analyzed by PCR-flow fluorescence hybridization. At the same time, DNA sequencing was used to analyze the type of HBD mutation.Results:The results of hematological phenotypes analysis showed that MCV was 87.9 fl, MCH was 29.3 pg, and Hb content was 140 g/L. The results of Hb typing showed that the contents of Hb F, Hb A 2, Hb A 2 variant, and Hb A were 0.4%, 1.3%, 0.6%, and 97.7%, respectively. No abnormality was found in α-thalassemia and β-thalassemia genes by routine deletion and mutation detection. According to DNA sequencing analysis, the patient had HBD: c.349 C>G variant. Conclusion:The low Hb A 2 content (reference value is 2.5% - 3.5%) in this case is due to the mutation of HBD, HBD: c.349 C>G variant is rare in Chinese population.