Thalassemia is a genetic blood disorder characterized by abnormal formation of hemoglobin where the synthesis of one of the polypeptide chains that form hemoglobin is decreased. This results in destruction of red blood cells (RBCs), which results in anemia. Thalassemia can be categorized into 2 major types: alpha and beta thalassemia. Alpha thalassemia occurs when a gene or genes related to alpha globin protein are missing or mutated. Beta thalassemia occurs when genetic defects affect beta globin protein production.

Beta thalassemia is further categorized into types based on symptom severity: beta thalassemia major (Cooley anemia), intermedia, and minor. Patients with thalassemia minor are usually asymptomatic and do not require treatment. Patients with thalassemia intermedia have a milder degree of anemia, and patients with thalassemia major have severe anemia.

In beta thalassemia intermedia, the signs and symptoms present in early childhood or later in life. Affected individuals may have mild-to-moderate anemia and delayed growth and bone abnormalities due to extra-medullary hematopoiesis.

Beta thalassemia major usually becomes clinically apparent within the patient's first 2 years of life. The typical clinical presentation consists of an infant developing life-threatening anemia with failure to thrive and jaundice. Patients may have splenomegaly, hepatomegaly, cardiomegaly, and bone malformations. Some adolescents experience delayed puberty. Many people with thalassemia major require chronic blood transfusion therapy to replenish their RBC supply. Over time, blood transfusions can lead to complications such as buildup of iron in the body, resulting in liver, heart, and hormone issues.

Beta thalassemia occurs more frequently in individuals from North Africa, India, Central Asia, Southeast Asia, the Middle East, and Mediterranean countries. Caused by HBB gene mutations, it is inherited in an autosomal recessive pattern.

Treatment is dependent on the type and its severity.