When 3 of the 4 alpha- globin genes are missing, malfunctioning or defective there is a severe lack of alpha-globin in RBC’s and excess beta chains. This leads to the formation of an abnormal type of haemoglobin known as haemoglobin H. Haemoglobin H is comprised of 4 beta-globin chains instead of the normal formation with 2 beta- globins and 2 alpha-globins. Haemoglobin H does not carry oxygen properly, making it useless to the RBC. It also causes damage to the cell membrane leading to rapid degradation of the RBC. Individuals who have haemoglobin H disease generally have a persistent state of anemia and require chronic blood transfusions to survive.