 Alpha thalassemia is a genetic condition caused by a lack of alpha-globin genes on chromosome 16. This leads to a decrease in the production of alpha-globin chains, resulting in a low level of hemoglobin anemia. There are several different types of alpha-thalassemia, ranging from mild to severe forms. The most severe form is HBH disease, where there is a complete absence of alpha-globin chains. Other forms include alpha-thalassemia trait, where only one copy of the gene is missing, and silent alpha-thalassemia, where two copies of the gene are missing, but the individual does not show any symptoms. In addition, compound heterozygous carriers of alpha-thalassemia can also develop anemia if they are exposed to certain environmental factors such as malaria. This article was authored by Hicks Douglas R. and Harteveld Cornelis L.