Thalassemia

A family of inherited blood disorders that is characterized by decreased production of either alpha or beta-globin chains of the hemoglobin molecule. The two major types of thalassemias are alpha_thalassemia (decreased alpha chain production) and beta_thalassemia (decreased beta chain production). The decreased hemoglobin production results in microcytic (low MCV; <80) red blood cells. Underproduction of one globin chain typically results in stimulating the bone marrow to increase its production of RBCs (as opposed to iron deficiency anemia where there is typically a decrease in RBCs). Hence, in cases of thalassemia the ratio of MCV/RBC is typically lower (<13) than that seen in iron deficiency anemia (usually a ratio of >15).

Note: As opposed to hemoglobinopathy which produces abnormal hemoglobin molecules, the hemoglobin molecules produced in thalassemias are decreased but normal in function.