Analysis Of δ-Globin Gene Mutations in the Chinese Population

Abstract

Although δ-globin gene (HBD MIM#142000) mutations have no immediate physical consequence, it can interfere with the diagnosis of β-thalassemia (β-thal), which can be severe. In the present study, of 40,863 samples referred for thalassemia trait screening, 167 samples with lower than expected Hb A2 levels, in the presence or absence of a second Hb A2 fraction, were selected for our analysis and 152 samples (0.4%) were positive for δ-globin gene mutations. Twenty-one different mutations were detected, and of these 12 have not been previously described. We found that −77 (T>C) was the most common mutation in Chinese followed by −30 (T>C), together accounting for almost 82.3% of the total number of δ-globin gene defects. Since compound heterozygotes for β-thal and a δ-globin gene mutation may have low mean cell volume (MCV) and normal Hb A2 levels, and therefore be overlooked as β-thal heterozygotes, a detailed molecular analysis for both α- and β-thal is necessary, especially when one partner has been identified to have β-thal trait.