Thalassemia

The thalassemias are a diverse group of genetic diseases characterized by absent or decreased production of normal hemoglobin, resulting in a microcytic anemia. The alpha‐thalassemias are caused by a decrease in the production of alpha‐globin due to a deletion or mutation of one or more of the four alpha‐globin genes located on chromosome 16. Beta‐thalassemia is caused by mutations in the beta‐globin gene. Delta beta thalassemia trait will lead to microcytosis (due to beta‐thalassemia trait) without anemia (due to the increase in hemoglobin F). Newborn screening identifies patients with beta‐thalassemia major, hemoglobin H, and sickle cell disease. Patients with beta‐thalassemia major and sickle cell disease will be asymptomatic at birth due to high fetal hemoglobin levels but will become symptomatic over the next 2–3 months as normal production of hgb F wanes.