Answer:
Step-by-step explanation:
Thalassemias are a group of genetic disorders that affect the production of hemoglobin, the protein in red blood cells that carries oxygen throughout the body. There are four main types of thalassemia: alpha thalassemia, beta thalassemia, delta-beta thalassemia, and gamma-delta-beta thalassemia.
The clinical manifestations of thalassemias are caused by defects in the protein structure of hemoglobin, which can result in the production of abnormal or insufficient amounts of hemoglobin. Specifically, these defects are usually caused by mutations in the genes that encode the alpha and beta globin chains of hemoglobin.
In alpha thalassemia, there is a deficiency in the production of alpha globin chains due to mutations in one or more of the four alpha globin genes. This leads to an excess of beta globin chains, which form aggregates that damage the red blood cells and cause anemia.
In beta thalassemia, there is a deficiency in the production of beta globin chains due to mutations in the beta globin gene. This results in the production of abnormal hemoglobin molecules that cannot function properly, leading to anemia and other clinical symptoms.
Delta-beta thalassemia and gamma-delta-beta thalassemia are rare forms of thalassemia that result from mutations in both the beta globin gene and either the delta globin gene or the gamma globin gene. These mutations can cause a wide range of clinical manifestations, depending on the specific nature of the mutation and the resulting abnormal hemoglobin molecules.
Overall, the clinical manifestations of thalassemias are caused by defects in the protein structure of hemoglobin that result in the production of abnormal or insufficient amounts of hemoglobin. These defects are usually caused by mutations in the genes that encode the alpha and beta globin chains of hemoglobin.