Alpha thalassaemia

Alpha thalassaemia is the consequence of an inherited defective synthesis of alpha globin, one of both specific protein chains of the haemoglobin molecule. It is controlled by four genes This disorder is mainly caused by deletions of the alpha genes, and shows variable clinical presentation according to the number of affected genes: alpha thalassaemia trait or alpha + (deletion of 1 or 2 genes) with microcytosis, normal HbA2 and HbF; there is no clinical manifestations, b) Hb H disease (deletion of 3 genes) is characterized by severe chronic haemolytic anaemia and c) Hydrops fetalis (deletion of 4 genes) which causes in utero death between the 5th month of pregnancy and birth.
Acquired alpha-thalassaemia is the best characterized of the acquired red blood cell disorders in patients with haematologic malignancy, and it is almost always associated with a myelodysplastic syndrome (MDS).

Synonym: Haemoglobin H