Thalassemia is a group of genetic diseases that decrease the production of some of the globin chains, which make up hemoglobin, and are the most frequent genetic disorders worldwide. Thus, thalassemias produce a decrease in hemoglobin. This is a molecule found in red blood cells or red blood cells, which is made up of four parts called chains: two alpha chains and two beta chains. Depending on the chain in which the defect occurs, we can find ourselves before:
Alpha thalassemia: occurs when there is insufficient production of alpha-globin. It is most prevalent in areas of Southeast Asia and China, the Middle East, and Africa. Beta thalassemia: is caused by an altered production of beta-globin. This thalassemia is frequent in Spain and other countries in the Mediterranean area.
Diseases that produce a decrease in hemoglobin, whose function is to transport oxygen to the tissues, cause different types of anemia. Therefore, the symptoms produced by thalassemia will be the same as anemia, although there are differences depending on the kind of chain affected and the degree of involvement:
People with thalassemia trait or thalassemia minor (heterozygotes or carriers of a defective gene for beta-chain production) may not develop anemia or mild anemia, so they may not have any symptoms. It is the most common form of the disease.
Homozygotes, carriers of two defective genes, suffer from thalassemia major, a severe disease since they cannot form beta chains that work correctly. When the body detects bad red blood cells, it destroys them. The bone marrow, where the blood cells are generated, tries to compensate by producing more red blood cells, which ends up causing an excessive growth that has complications such as deformities and bone fractures in childhood and enlargement of the liver and spleen as they try to help the bone marrow make more red blood cells. This can become incompatible with life and lead to death at an early age.
Thalassemia: Difference Between Normal Blood and Thalassemia Disease
Each alpha chain of hemoglobin is made up of two different parts, so we have two genes from each parent. This means it is more challenging to have a higher grade of alpha thalassemia since we would have to inherit twice as many defective genes as in beta-thalassemia.
People with alpha thalassemia trait or alpha-thalassemia-1 don’t have any symptoms and usually don’t show any abnormalities in their red blood cells. Those with two defective genes or who have alpha-thalassemia-2 show symptoms and manifestations similar to beta thalassemia trait, so they will only have mild anemia or a slight alteration in the size of the red blood cells.
Those who suffer from the mutation of three genes of the alpha chain of hemoglobin produce hemoglobin called H, or HbH, suffer from moderate-severe anemia, similar to an intermediate degree of beta-thalassemia, and can reach adulthood.
The mutation of the four genes that produce the alpha chains causes the death of the fetus before birth.
How is it diagnosed?
For the confirmation diagnosis of thalassemia, a specific study of hemoglobin is required, which will be requested when anemia with tiny red blood cells appears in analysis and iron is expected since small red blood cells appear only in thalassemias and in anemias, iron deficiency, or due to lack of iron.
How it is treated
Treatment will depend on the degree of involvement:
Generally, the thalassemia trait (beta or alpha) does not require any treatment. Patients with HbH require occasional blood transfusions. Over time, removal of the spleen or splenectomy may be necessary. People with beta-thalassemia major require frequent blood transfusions from infancy. This produces a severe iron overload that generates problems such as diabetes, cirrhosis, and heart disease. For this reason, treatment with drugs that eliminate iron from the body, or chelators, is also needed, and it may become necessary to perform a splenectomy. In addition, treatment with folic acid is usually associated with helping generate red blood cells.
Finally, in the case of couples who suffer from thalassemia traits and want to have children, genetic counseling can help avoid offspring with thalassemia major. If their disease is discovered late in the pregnancy, a genetic study of the fetus for thalassemia major may be performed so that the couple can decide whether to continue or terminate the pregnancy.