An Account On Thalassemia:
Thalassemia is an inherited disorder of the blood wherein the total RBC count, the production of hemoglobin, and thus the oxygen-carrying capacity of blood decreases. There is the destruction of RBCs as a result of which anemia occurs. Thalassemia may occur either due to the absence or deletion of the gene or mutation of single or multiple genes.
Types Of Thalassemia:
Thalassemia is basically of two main types:
- Alpha thalassemia comprising of hemoglobin H and hydrops fetalis as its subtypes
- Beta thalassemia consisting of primary and intermediate forms as subtypes
Thalassemia minor is also found in some cases.
Factors Responsible For Thalassemia:
- General Cause of Thalassemia is an inherited chromosomal disorder. And it occurs due to a defect in the genes of either of the parents.
- If only one parent suffers from Thalassemia, Thalassemia minor will be manifested in the fetus, and the child will act as a carrier for Thalassemia. However, if both parents suffer from Thalassemia, thalassemia major is displayed, and the child suffers from a more acute case of Thalassemia.
- Alpha Thalassemia causes: This form of Thalassemia is associated with anemia of several types and intensities. In Thalassemia, the hemoglobin is destroyed because of the improper synthesis of globin chains. Hemoglobin molecule consists of four globin chains(alpha, beta, gamma and delta chains), thus its a tetramer. The faulty production of the alpha-globin chain leads to alpha thalassemia.
- Alpha Thalassemia occurs due to the deletion of the two genes, namely, HB1 and HB2 genes. The alleles of HB1 and HB2 gene is present in the cells of humans. One allele inherited from the father and another allele from the mother makes up for the four alleles required for the synthesis of the alpha-globin chain. Alpha thalassemia comprises of two forms, hemoglobin H and Hydrops fetal.
- Hb Bart syndrome is an aggravated form of alpha thalassemia. In this condition, there is the destruction of either three or all four alleles required for hemoglobin synthesis. As a result, normal hemoglobin is not produced. Instead, abnormal hemoglobin is formed called a hemoglobin H or hemoglobin Bart. It results in anemia but a mild form.
- Hydrops Foetalis- This condition is mostly witnessed in the prenatal stage of a fetus. It occurs when the four genes responsible for the alpha-globin chain are destroyed because there have been cases of stillborn babies or death of babies just after parturition.
- Beta Thalassemia occurs due to the faulty synthesis of a beta-globin chain of hemoglobin. Beta Thalassemia is also referred to as Cooley’s Anaemia.
- Thalassemia major – It is one of the most acute forms of beta-thalassemia. It’s associated with very severe anemia and also causes hepatosplenomegaly. It is an autosomal recessive disorder associated with the mutation in HBB genes. Here both HBB genes are affected. In this condition, the patient might require a blood transfusion.
- Thalassemia Minor- Most of these patients have a mutation in one HBB gene and are usually carriers of Thalassemia, but no symptoms are seen in them in most cases. However, under rare circumstances, signs might be seen. The most common manifestation is anemia.