Low affinity haemoglobin

**Definition:** A disease caused by determinants arising after birth, in the antenatal period or by genetically inherited factors leading to low oxygen affinity haemoglobin. This disease is characterised by abnormalities in the globin chains that alter the affinity of the haemoglobin molecule for oxygen, affecting the normal loading of oxygen in the lungs and delivery of oxygen to the tissues. This disease may present with fatigue, muscle weakness, loss of appetite, weight loss, diarrhoea, nausea, fast heartbeat or numbness in extremities.