Beta Thalassemia Major (Cooley Anemia)

Thalassemia and sickle cell disease are some of the most common single-gene inherited hemoglobin disorders worldwide. Unlike sickle cell disease, which is a qualitative globin chain defect, thalassemia results from quantitative defects (beta+ and beta0) in one or more globin chains of hemoglobin and causes hypochromic microcytic anemia. Dr. Cooley was the first to report beta-thalassemia in Detroit in 1925, hence coined the name Cooley anemia. It is more prevalent in Mediterranean descent, Middle Eastern, and Asian populations. It was hypothesized that it started off in the United States, not in the Mediterranean because the clinical features were cloaked by malaria, which has a similar presentation. In contrast, Central Africa was the origin of sickle cell disease. Due to changing demographics, these two diseases are now major health concerns around the globe. The thalassemia disease varies both genotypically and phenotypically due to the detection of more than 200 globin gene mutations so far. Based on clinical and laboratory findings, thalassemia has been classified into three main types, which include beta-thalassemia minor, beta-thalassemia intermedia, and beta-thalassemia major (homozygous condition). Based on severity, the thalassemia intermedia and thalassemia major (TM) are further classified into transfusion-dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT) respectively. The spectrum of severity ranges from mild anemia to moderate and severe anemia. Its clinical features include severe hemolytic anemia, bone abnormalities, and hepatosplenomegaly (HSM).