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.

• δ-Thalassemia (δ-thal)
• δ-Globin gene variant
• Mutation detection
• HBD gene