Thalassemia develops as a result of structural impairments of protein chain of hemoglobin secondary to a defect in hemoglobin-producing genes. All human beings have 46 chromosomes – structures that code our features. In fact, these chromosomes are 23 pairs. All human beings have a pair of 23 chromosomes. As a result, human beings have one pair of each gene that determines our features. There are also 2 hemoglobin-producing genes. The person will be completely normal if both hemoglobin-producing genes are normal.
If there is a problem with one of these hemoglobin-producing genes, the person will have thalassemia trait – carrier in other words-, and if there is a problem with both of these genes, thalassemia or Familial Mediterranean Fever occurs. Both mother and father should have carrier status for this condition. If a thalassemia carrier marries a person with normal hemoglobin-producing gene, their children will be carrier by 50% possibility at most. However, when a carrier person marries another carrier person, possibility of thalassemia will be 25 %, possibility of carrier status will be50 %, and children will be healthy with possibility of 25 %. Therefore, people with diagnosed carrier status are duly informed and referred to large-scale centers, where they can get genetic counseling and have tests, if they are getting married with people with same status.
Thalassemia, also referred as Familial Mediterranean Anemia, occurs secondary to decreased production of protein chain of hemoglobin molecule, which is caused by an abnormality in the hemoglobin-producing gene. Depending on severity of abnormality in hemoglobin-producing genes, protein is not produced or produced insufficiently. Those abnormalities are manifested in thalassemia at varying severity levels.
First one is thalassemia trait. Normally, human beings have 23 pairs of chromosomes, or human beings have a pair of each gene. There are also 2 hemoglobin-producing genes. If disease is carried through only one, then the person becomes carrier. The person has no complaint; this condition is incidentally diagnosed on complete blood count, which is analyzed for various reasons, and the condition is characterized with minimal anemia, small sized erythrocytes and normal or elevated erythrocyte count.
Thalassemia is called by our population as Familial Mediterranean Anemia. As the name implies, it is a hereditary disease. It is inherited from parents. It is common at Mediterranean geography and it is associated with anemia.
How it occurs?
First of all, we have to talk about the structure of hemoglobin. The molecule “hemoglobin” gives red color to our blood and carries oxygen to our tissues. This molecule consists of two parts. One is iron “Hem” part, and the other one is protein “Globin” part. Globin part, made of protein, is comprised of 2 protein chains. Hemoglobin A is the most common type of hemoglobin in adults. Hemoglobin A consists of 2 Alpha and 2 Beta protein chains. The disease is named to refer impaired globin chain. If Beta chain is impaired, the disease is called Beta-thalassemia, or if Alpha chain is impaired, then the disease is called Alpha-thalassemia, and thalassemia also refers less common impairment of other hemoglobin types, such as FA2, albeit rare. Impairment of hemoglobin-producing gene is necessary for any abnormality of those chains. As a result of this impairment, whether familial or acquired, production of protein chains will decrease, resulting with different types of the disease, which vary in terms of severity.