Haemoglobinopathy
Hemoglobinopathy is a kind of genetic defect that results in abnormal
structure of one of the globin chains of the hemoglobin molecule. It is a collection of a number of diseases, especially Sickle cell anemia and Thalassemia. Symptoms vary for the different diseases: in sickle-cell anemia the red blood cells tend to assume a different shape under anaerobic conditions, leading to organ damage and circulatory problems, while in thalassemia there is inneffective production of red blood cells (ineffective erythropoiesis).
The hemoglobinopathies (and also related diseases like glucose-6-phosphate dehydrogenase deficiency) seem to have given an evolutionary benefit, especially to heterozygotes, in areas where malaria is endemic. Malaria parasites live inside red blood cells, but subtly disturb normal cellular function. In patients predisposed for rapid clearance of red blood cells, this may lead to early destruction of cells infected with the parasite and increased chance of survival for the carrier of the trait.
Despite the malaria link, Caucasians can be affected by hemoglobinopathies (Thalassemia occurs in the Meditteranian countries), as can people from South America and India.
