alpha-thalassemia

noun

al·​pha-thal·​as·​se·​mia

variants also α-thalassemia

ˌal-fə-ˌtha-lə-ˈsē-mē-ə 

: thalassemia in which the hemoglobin chains designated alpha are affected

Note: The severity of alpha-thalassemia is directly related to the number of defects occurring in the four genes controlling synthesis of the alpha hemoglobin chain. Defects in one or two of the genes causes a condition that is asymptomatic or marked by mild anemia. Defects in three of the genes cause a condition marked by hemolytic anemia and enlargement of the spleen. Defects in all four genes is fatal and results in a fetus that is stillborn or critically ill with hydrops fetalis.

compare beta-thalassemia