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

BackgroundDeletional hereditary persistence of fetal hemoglobin (HPFH)/delta beta-thalassemia and delta-thalassemia are rare inherited disorders which may complicate the diagnosis of beta-thalassemia. The aim of this study was to reveal the frequency of these two disorders in Southwestern China. MethodsA total of 33,596 subjects were enrolled for deletional HPFH/delta beta-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 delta-globin gene. Positive samples with low Hb A(2) levels were confirmed by delta-globin gene sequencing. Furthermore, the pathogenicity and construction of a selected delta-globin mutation were analyzed. ResultsA total of 92 suspected cases with Hb F >= 5.0% were further characterized by MLPA. Eight different deletional HPFH/delta beta-thalassemia were observed at a frequency of 0.024%. In addition, 195 cases suspected to have a delta-globin gene mutation (Hb A(2) <= 2.0%) were characterized by molecular analysis. delta-Globin gene mutation was found at a frequency of 0.49% in Yunnan. The pathogenicity and construction for a selected delta-globin mutation was predicted. ConclusionScreening of these two disorders was analyzed in Southwestern China, which could define the molecular basis of these conditions in this population.