THALLASSEMIAs Flashcards
What is thalassaemia?
A group of inherited disorders of hemoglobin characterized by reduced or absent production of one or more globin chainsineffective erythropoiesis
What is the origin of the word “thalassaemia”?
Derived from the Greek word Thalassa for “sea”; initially thought to occur only in Mediterranean populations.
Who first described thalassaemia?
Dr. Thomas Cooley in 1925 in children of Italian descent.
What is homozygous thalassaemia major also called?
Cooley’s anemia.
Why is thalassaemia a global public health problem?
It is common in tropical regions and is the most prevalent single-gene disorder worldwide.
What are the two main classifications of thalassaemia?
By the deficient globin chain (e.g. α
Which regions have the highest prevalence of β-thalassaemia?
Mediterranean Southeast Asia
Which regions have the highest prevalence of α-thalassaemia?
Southeast Asia Eastern Mediterranean
Why is thalassaemia common in malaria-endemic areas?
Heterozygotes have a survival advantage against malaria leading to high gene frequency.
What are the clinical forms of β-thalassaemia?
β-thalassaemia major β-thalassaemia intermedia
What genetic mutations cause β-thalassaemia major?
Point mutations leading to genotypes such as βo/βo
βo/β+
What is the main pathogenesis of β-thalassaemia major?
Excess free α-chains precipitate in erythroblasts and red cells damaging membranes and leading to hemolysis and ineffective erythropoiesis.
What causes skeletal deformities in β-thalassaemia major?
Extreme bone marrow hyperplasia due to anemia and hypoxia causing skull and facial bone deformities.
What causes iron overload in β-thalassaemia major?
Increased iron absorption due to ineffective erythropoiesis and regular blood transfusions.
What are the clinical features of β-thalassaemia major?
Anemia failure to thrive
What is α-thalassaemia?
A disorder caused by reduced or absent production of α-globin chains involving up to four α-gene loci on chromosome 16.
What are the forms of α-thalassaemia?
Hb Bart’s hydrops fetalis syndrome (–/–) HbH disease (–/-α)
What is Hb Bart’s hydrops fetalis syndrome?
The most severe form of α-thalassaemia causing stillbirth or neonatal death due to anemia
What laboratory features are seen in β-thalassaemia major?
Low Hb
microcytic hypochromic anemia
What does Hb electrophoresis show in β-thalassaemia major?
Elevated HbF (10-98%) variable HbA2
What are common screening tests for thalassaemia?
MCV MCH
What are key strategies for thalassaemia prevention?
Health education carrier screening
What is the principle of “hyper-transfusion” in β-thalassaemia?
Regular blood transfusions to maintain Hb >10 g/dL preventing anemia and skeletal deformities.
What are complications of iron overload in β-thalassaemia?
Damage to the liver heart
What drugs are used for iron chelation in thalassaemia?
Desferrioxamine and Deferiprone.
What is the only curative therapy for thalassaemia?
Haemopoietic stem cell transplantation (HSCT).
What experimental therapies are under study for thalassaemia?
HbF production enhancement (e.g. hydroxyurea) and gene therapy to replace abnormal genes.
What are the differential diagnoses of thalassaemia?
Iron deficiency anemia sickle cell disease
