Hb Barika [α42(C7)Tyr→His (α2)] Leads to an α⁺-Thalassemia-like Syndrome

Abstract

In human deoxyhemoglobin (deoxyHb), the hydrogen bond between Aspβ99(G1) and Tyrα42(C7), located in the α1β2 interface, is crucial for the stability of the T structure. All the variants that could arise from a single point mutation affecting codon β99 have already been observed, leading always to erythrocytosis. Conversely, up to now, Hb Barika is the only example found in a patient in whom the α42 is mutated. From a biochemical point of view, for theoretical reasons, this substitution has already been extensively studied on recombinant hemoglobin (rHb). In the patient, Hb Barika is expressed at a level lower than expected for an α2 gene variant and leads to an α⁺-thalassemic-like syndrome.

Keywords:

• Hemoglobin (Hb) variants
• α-Thalassemia (thal)
• Unstable hemoglobin (Hb)
• Recombinant hemoglobin (rHb)