Hemoglobinopathies Flashcards
What are hemoglobinopathies?
A genetic disorder of defective globin chains required for normal hemoglobin synthesis.
Hemoglobinopathies can be classified into qualitative and quantitative types.
What are qualitative hemoglobinopathies?
Production of structurally abnormal hemoglobin molecules due to gene substitution. Examples include Sickle cell HbS disease, HbC, and HbE disease.
These disorders involve mutations that alter the structure of the hemoglobin.
What are quantitative hemoglobinopathies?
Insufficient quantities of normal hemoglobin being synthesized due to gene deletion, such as in Thalassemias.
These conditions result in reduced production of hemoglobin, leading to anemia.
What is Thalassemia?
A congenital disorder where a mutation causes decreased or absent synthesis of globin chains.
Patients may present with various symptoms depending on the severity of the genetic defects.
What are the two main types of thalassemia?
Alpha (α) thalassemia and Beta (β) thalassemia.
Each type is classified further into major and minor forms based on severity.
What is β Thalassemia Major (Cooley’s anemia)?
A condition characterized by severe microcytic, hypochromic anemia with hemoglobin levels around 60-90 g/L.
Lab findings include increased RDW and peripheral blood film showing erythrocytosis.
What is α Thalassemia Major (α0)?
A severe form where both α chains are affected, leading to fatal anemia, often resulting in hydrops fetalis.
The fetus typically presents with severe edema and hepatosplenomegaly.
What is Hb H disease?
A form of α thalassemia intermedia characterized by the formation of β4 chains due to lack of α chains.
Hb H is unstable and can precipitate, leading to splenomegaly.
What is hemoglobin electrophoresis?
A diagnostic tool used for identifying various types of hemoglobinopathies by separating hemoglobin on a gel medium.
It allows for the detection of different hemoglobin variants based on their migration patterns.
What is sickle cell anemia?
A beta chain variant where valine is substituted for glutamic acid on the beta chain, causing red blood cells to sickle under deoxygenated conditions.
This disorder is most common in individuals of African ancestry.
What is the testing method for sickle cell disease?
Sodium metabisulfite test and solubility test are used to detect sickling.
Hemoglobin electrophoresis can confirm the diagnosis by quantifying HbS.
What characterizes Hemoglobin C disease?
A substitution of lysine for glutamic acid in the beta chain, resulting in mild anemia and hemoglobin C crystals.
This condition is also more common in individuals of African ancestry.
What are the lab findings for HbC disease?
Moderate anemia with >90% HbC, splenomegaly, and gallstones due to increased bilirubin.
Peripheral blood film may show coffin-shaped hemoglobin crystals.
Fill in the blank: The most common type of hemoglobin in adults is _______.
HgbA
True or False: α Thalassemia Major is a condition where there is an excess of α chains.
False
