They would, however, have a very difficult time succeeding in constant-output activities, such as distance running or wrestling. There are many congenital hemoglobin disorders. Sickle cell anemia is perhaps the most common and best known. Having an abnormal hemoglobin does not always make you anemic, and this is true of most of the thalessemias. The inheritance of thalessemias is quite complex.
Abnormal hemoglobin can result in four types of alpha thalessemia and two types of beta thalessemia.
Alpha thalessemia genes are found in Southeast Asians, blacks, and people originally from the Middle East. This last type is usually seen only in Southeast Asians. Someone with only one of the beta genes will have beta thalessemia trait, a mild anemia in which the red cells are smaller than normal. Because small red cells are also typical of iron deficiency anemia, which is extremely common in women and children, many people with this trait are erroneously diagnosed as iron deficient, and are given iron pills. Iron not only doesn't help this mild anemia, but it can build up in the tissues.