Hb A₂-Pasteur-Tunis [δ59(E3)Lys→Asn, AAG→AAC]: A New δ Chain Variant Detected by DNA Sequencing in a Tunisian Carrier of the Codon 39 (C→T) β⁰-Thalassemia Mutation

Abstract

We describe a new δ-globin variant, Hb A₂-Pasteur-Tunis [δ59(E3)Lys→Asn, AAG→AAC]. This hemoglobin (Hb) displayed an electrophoretic mobility faster than normal Hb A₂ and was expressed at 2.2 %. The molecular defect was characterized by DNA sequencing and confirmed by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-designed protocol. Hb A₂-Pasteur-Tunis was found in a carrier of a codon 39 (C→T) β⁰-thalassemia (thal), presenting with a normal Hb A₂ level. Phenotype and genotype investigations revealed that the total Hb A₂ level of the patient was that expected for a minor β-thal (4.8%).

Keywords:

• Hb A₂ variant
• β-Thalassemia (thal)
• Sequencing
• Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)