Analysis of deletional hereditary persistence of fetal hemoglobin/δβ-thalassemia and δ-globin gene mutations in Southerwestern China

Abstract

Background: Deletional hereditary persistence of fetal hemoglobin (HPFH)/δβ-thalassemia and δ-thalassemia are rare inherited disorders which may complicate the diagnosis of β-thalassemia. The aim of this study was to reveal the frequency of these two disorders in Southwestern China. Methods: A total of 33,596 subjects were enrolled for deletional HPFH/δβ-thalassemia, and positive individuals with high fetal hemoglobin (Hb F) level were diagnosed by multiplex ligation-dependent probe amplification (MLPA). A total of 17,834 subjects were analyzed for mutations in the δ-globin gene. Positive samples with low Hb A2 levels were confirmed by δ-globin gene sequencing. Furthermore, the pathogenicity and construction of a selected δ-globin mutation were analyzed. Results: A total of 92 suspected cases with Hb F ≥5.0% were further characterized by MLPA. Eight different deletional HPFH/δβ-thalassemia were observed at a frequency of 0.024%. In addition, 195 cases suspected to have a δ-globin gene mutation (Hb A2 ≤2.0%) were characterized by molecular analysis. δ-Globin gene mutation was found at a frequency of 0.49% in Yunnan. The pathogenicity and construction for a selected δ-globin mutation was predicted. Conclusion: Screening of these two disorders was analyzed in Southwestern China, which could define the molecular basis of these conditions in this population.