Thalassemia refers to a group of inherited disorders in which the amount of hemoglobin produced in the body is greatly reduced. It occurs due to a defect in the synthesis of hemoglobin chains. There are two main types of thalassemia: Alpha and beta-thalassemia.
Alpha thalassemia occurs as a result of the deletion of the alpha-globin genes, which leads to a decrease in the synthesis of alpha-globin. There are two alpha genes, if one is deleted, it is known as Alpha +, if both genes are knocked out, it is known as Alpha 0.
Beta thalassemia occurs when there is a mutation of the beta gene, which leads to reduce the production of beta-globin. When there is a partial loss, it is known as Beta +, but when there is a complete loss of function, it is known as Beta 0 thalassemias.