Characterization of Hb Calvino (HBB: c.406G > A): A New Silent β-Globin Gene Variant Found in Coexistence with α-Thalassemia in a Family of African Origin

Abstract

We report a new silent β-globin gene variant found in a family from Angola living in the north eastern Italian city of Ferrara. The probands, two young sisters, presented with hematological parameters compatible with a β-thalassemia (β-thal) minor but with normal Hb A₂ levels and normal hemoglobin (Hb) separation on high performance liquid chromatography (HPLC). Molecular analyses revealed a homozygosity for the common –α^3.7 (rightward) deletion and heterozygosity for a novel transition (GCT > ACT) at codon 135 of the β-globin gene, leading to an Ala → Thr single amino acid substitution that was inherited from the healthy father.

• α-Thalassemia
• (α-thal)
• β-globin variant
• angolan-Mozambican origin
• missense mutation

Acknowledgements

This study has been conducted according to the local ethical regulations and with full consent of the family. The authors wish to thank Mrs. Cinzia Tonioli (Department of Clinical and Experimental Medicine, Section of Pediatrics, University of Ferrara, Ferrara, Italy) for her helpful secretarial assistance.