Characterization of Three Novel δ Chain Hemoglobin Variants and Two δ-Thalassemia Alleles

Abstract

We report the characterization of five novel δ-globin gene mutations detected during routine screening for thalassemia. Three missense mutations were identified, resulting in the following δ chain hemoglobin (Hb) variants: Hb A₂-Acacias [δ4 (ACT>AGT), Thr→Ser, HBD c.14C>G], Hb A₂-Toronto [δ74 (GGC>GAC), Gly→Asp, HBD c.224G>A], and Hb A₂-Calgary [δ99 (GAT>GGT), Asp→Gly, HBD c.299A>G]. Two other mutations most likely result in δ⁰-thalassemia (δ⁰-thal). One mutation altered the translation initiation codon from ATG to ATA (HBD c.3G>A), and another changed the canonical splice donor sequence of IVS-II from GT to AT (HBD C.315+1G>A).

Keywords:

• δ Chain variants
• δ-Thalassemia (δ-thal)
• Mutations