Haemoglobin is the component in red cells that is responsible for transporting oxygen from the lungs to all parts of the body. Normal haemoglobin comprises of two α globin chains and two β globin chains, and each of these protein chains carry an iron-containing haem group which binds to oxygen.
Haemoglobinopathies are a group of inheritable conditions which affect the quantity and/or structure of the haemoglobin. The most common haemoglobinopathy in Singapore and Southeast Asia is thalassaemia. In each individual, there are four α genes (two inherited from each parent) and two β genes (one inherited from each parent). They signal the production of the α globin chains and β globin chains respectively in haemoglobin. Persons with thalassaemia mutations of the α globin genes (α thalassaemia) have reduced production of α globin chains and those with thalassaemia mutations of the β globin genes (β thalassaemia) have reduced production of β globin chains, resulting in decreased quantities of haemoglobin.