Further Characterization of Hb Bronovo [α103(G10)His→Leu; <i>HBA2</i>: c.311A&gt;T] and First Report of the Homozygous State

Hb Bronovo [α103(G10)His→Leu, <i>HBA2</i>: c.311A>T] is an α-globin variant that interferes with and decreases binding efficiency to α hemoglobin (Hb) stabilizing protein (AHSP), a chaperone molecule. The histidine residue at position 103 is integral to the AHSP hydrogen bond formation where disruption results in an increased quantity of cytotoxic free α-globin chains, thereby creating a similar pathophysiology as β-thalassemia (β-thal). We report a family with Hb Bronovo, including a homozygous proband, which resulted from maternal uniparental disomy (UPD). Although not detected by routine studies in previous reports, the variant protein is visible by intact mass spectrometry (MS).