Haemoglobinopathies: genetic and clinical aspects with an impact on blood transfusion

Abstract

The haemoglobinopathies are autosomal recessive genetic disorders resulting in qualitative or quantitative change in the haemoglobin (Hb) molecule. HbS, the most widespread structural haemoglobin variant, hinders microcirculation by causing a sickle shape of red cells. In sickle cell disease, blood transfusion should be done only for strict indications. In thalassaemias, Hb synthesis is impeded by defective production of globin chains. The commonest types of clinical importance are α‐, βδ‐ and β‐thalassaemia. Compound heterozygotes for thalassaemia and Hb variants may have varying clinical impact.Morbidity is related to the anaemia, complications of blood transfusions including iron overload and transfusion transmissible infections, and splenectomy.Treatment of homozygous β‐thalassaemia is based on regular blood transfusion from early childhood, placing a major workload for blood transfusion services. Stringent quality measures are necessary to ensure that the transfused product meets requirements.Greece's national registry records 4,506 thalassaemia major and intermedia, “Η” haemoglobinopathy and sickle cell disease patients. Thalassaemia patients consume 18% of total RBC supply. Incidence of transfusion associated adverse reactions is 250:100 000 units of RBCs. Allergic (87.6:100 000) and NHFTR (89.9:100 000) are most common. One sickle thalassaemia patient died of hyperhaemolysis syndrome. Eight patients died of HCV hepatocellular carcinoma. HIV was transmitted to one patient during the window period.