A case of hereditary persistence of fetal haemoglobin

Abstract

Thalassaemia syndromes comprise a large clinical spectrum and a well recognized observation is the inverse link between clinical severity and quantity of fetal haemoglobin (HbF) present1 . It is now known that three types of globin that produce haemoglobin (Hb) change from e-globin (epsilone) to g-globin (gamma) in the fetus and to b-globin (beta) around birth. This process of change is termed “globin switching”. Rarely, due to a genetic defect, the gglobin gene continues to function, producing gamma chains. Therefore HbF is present throughout life giving rise to the condition hereditary persistence of fetal haemoglobin (HPFH)2 . Such persons are often asymptomatic and lead normal lives. Persons with thalassaemia major who have concomitant HPFH have low transfusion requirements due to the persistence of HbF, making up for the deficiency of b-globin3 . HPFH provides a basis for a genetic approach to cure haemoglobinapathies in the future.