What is Delta thalassemia?
Delta beta (δβ) thalassemia is an infrequent cause of elevated fetal hemoglobin (HbF) beyond infancy. This disorder is characterized by reduction in production of both δ and β-globin chains, usually due to deletions of δ and β structural genes (1).
How does expression of γ globin protect against β thalassemia?
Because the severity of homozygous β-thalassemia is directly related to the imbalance between α- and β-globin chains, even the low levels of γ-globin in F cells reduce the relative excess of α-globin and provide a selective survival of cells making HbF at the time of ineffective erythropoiesis, in the most severe forms …
How is Delta Beta thalassemia diagnosed?
Diagnosis. Following the detection of hypochromic microcytic red blood cells, delta-beta thalassemia is confirmed by high-performance liquid chromatography.
What type of mutation causes beta thalassemia?
Beta thalassemia is caused by mutations in the hemoglobin beta (HBB) gene. Individuals with beta thalassemia minor have a mutation in one HBB gene, while individuals with the intermediate and major forms have mutations in both HBB genes.
What is Gamma thalassemia?
gamma delta beta-Thalassemia is a rare disorder of hemoglobin biosynthesis, characterized molecularly by partial or complete deletions of the beta-globin gene complex of 100 kilobases (kb) or greater. Common to all mutants described has been the deletion of the most-5′ sequences of the beta-globin complex.
What is alpha thalassemia?
Alpha thalassemia occurs when some or all of the 4 genes that make hemoglobin (the alpha-globin genes) are missing or damaged. There are 4 types of alpha thalassemia: Alpha thalassemia silent carrier. One gene is missing or damaged, and the other 3 are normal. Blood tests are usually normal.
Is beta thalassemia nonsense mutation?
A common mutation causing thalassemia in Mediterranean populations is an amber (UAG) nonsense mutation at the 39th codon of the human beta-globin gene, the beta-39 mutation.
What are types of thalassemia?
There are 2 main types of thalassemia: alpha and beta. Different genes are affected for each type. Thalassemia can cause mild or severe anemia. Anemia occurs when your body does not have enough red blood cells or hemoglobin.
What are the symptoms of beta thalassemia major?
Beta thalassemia major is caused by a homozygous mutation (beta-zero thalassemia) of the beta-globin gene, resulting in the total absence of beta chains. It manifests clinically as jaundice, growth retardation, hepatosplenomegaly, endocrine abnormalities, and severe anemia requiring life-long blood transfusions.
What causes Alpha and beta thalassemia on chromosome 11?
Alpha thalassemia is caused by deletions of alpha-globin genes, and beta thalassemias are caused by a point mutation in splice site and promoter regions of the beta-globin gene on chromosome 11. [4] Epidemiology
Which is milder coinheritance of alpha or beta thalassemia?
Coinheritance of alpha thalassemia: Beta-thalassemia patients with coinheritance of alpha thalassemia have a milder clinical course due to a less severe alpha-beta chain imbalance.
What is the role of HB in thalassemia?
Thalassemias are a heterogeneous grouping of genetic disorders that result from a decreased synthesis of alpha or beta chains of hemoglobin (Hb). Hemoglobin serves as the oxygen-carrying component of the red blood cells.