Two Novel δ-Globin Chain Variants Identified in the Chinese Population

The HBD gene (MIM#142000) encodes the δ-globin chain, a β-like subunit of the HbA2 fraction. In this study, we report two novel HBD variants identified in the Chinese population. Sanger sequencing revealed two types of novel mutations: [HBD:c.349C > A; CD 116 CGC > AGC (Arg > Ser)] and [HBD:c.201G > C; CD 66 AAG > AAC (Lys > Asn)]. Hemoglobin analysis by capillary electrophoresis indicated that the levels of HbA2 were reduced to 1.2%, while the percentages of the corresponding HbA2 variants were 0.5% and 0.7%. Neither of the two HBD mutations was associated with a decrease in mean corpuscular volume (MCV) or mean corpuscular hemoglobin (MCH). They have been named HbA2—Shenzhen and HbA2—Zhanjiang, respectively, according to their place of origin.