Haemoglobin D disease

**Definition:** Haemoglobin D (Hb D) disease is characterised by mild haemolytic anaemia and mild to moderate splenomegaly. Prevalence is unknown. Heterozygous forms of Hb D are clinically silent. Molecular testing can be useful to distinguish Hb D homozygosity from cases of heterozygous Hb D in association with beta-(0) thalassaemia.