A Phenotypically Unusual Hemoglobin H Disease Resulting from a Rare α-Globin Genotype (- SEA /-α 27.6 ).

Hemoglobin H (Hb H) disease is usually characterized by the existence of Hb H, which influences the degree of functional anemia. We here report a patient with a rare Hb H disease genotype (-SEA /-α27.6 ), who was observed to paradoxically have no detectable Hb H fraction on electrophoresis. To date, the reason why the quantity of Hb H component and the clinical presentation in Hb H disease vary widely is still incompletely understood. Our report demonstrates a possible explanation - the different degradation ability of excess β-globin chains, which might be regulated by the 27.6 kb sequence of α-globin gene.