Thalassemias are a group of genetic diseases that are among the most serious and common genetic conditions. These pathologies affect the genes that produce hemoglobin, an essential molecule found in red blood cells that is responsible for transporting oxygen to all the cells of the body.
In adults, 97% of hemoglobin is composed of four units called globins, two alpha-globins and two beta-globins. Each unit contains a heme group which is responsible for binding oxygen. The alpha globins are encoded by the HBA1 and HBA2 genes which are virtually identical, while the HBB gene produces the beta globins. The presence of pathogenic mutations in HBA1/HBA2 lead to alpha thalassemia and alterations in HBB cause beta thalassemia, both of which are the two main categories of thalassemias.
Although the first recorded cases of thalassemia were identified in the Mediterranean, it is a fairly common condition that has spread to other geographic areas such as Southeast Asia, the Middle East and China. It also tends to be found more frequently in people of African descent. The prevalence of thalassemia is almost 3 individuals per 100,000 inhabitants.
Symptoms can range from mild to severe depending on whether there is a total or partial loss of beta globin. Some patients show symptoms from birth while others may be asymptomatic or have mild microcytic anemia.
In mild or asymptomatic forms, treatment is, in many cases, unnecessary. However, in those cases with severe symptoms, regular blood transfusions, iron chelation therapy, splenectomy (removal of the spleen) and close follow-up with blood tests, magnetic resonance imaging, echocardiograms, ophthalmologic and audiological examinations, among other controls, may be required.