Thalassaemia Flashcards
How many globin chains are in haemoglobin and which types?
2 alpha
2 beta
What type of genetic condition is Thalassaemia? E.g. dominant
Autosomal recessive
What causes haemolytic anaemia in Thalassaemia?
the red blood cells are more fragile and break down easily, causing haemolytic anaemia.
What are the universal features of Thalassaemia? (7)
• Microcytic anaemia (low mean corpuscular volume)
• Fatigue
• Pallor
• Jaundice
• Gallstones
• Splenomegaly
• Poor growth and development
What is seen on an fbc in Thalassaemia? (2)
Microcytic anaemia
Some severe cases may have raised ferritin from iron overload
What test is used to diagnose globin abnormalities such as Thalassaemia?
Haemoglobin electrophoresis
Who is offered screening tests for Thalassaemia?
All pregnant women
What can cause iron overload in Thalassaemia? (2)
• Increased iron absorption in the gastrointestinal tract
• Blood transfusions
What symptoms and complications does iron overload cause in Thalassaemia? (6)
○ Liver cirrhosis
○ Hypogonadism
○ Hypothyroidism
○ Heart failure
○ Diabetes
○ Osteoporosis
What is the management of iron over load in Thalassaemia? (2)
Limiting transfusions
Iron chelation
Where are the genes that code for alpha globin found?
Chromosome 16
What are the types of alpha Thalassaemia and what degree of anaemia do each get? (3)
Carrier - asymptomatic
Haemoglobin H disease - moderate anaemia
Alpha Thalassaemia major - intrauterine death due to severe fatal anaemia
What is involved in the management of alpha Thalassaemia? (4)
• Monitoring
• Blood transfusions
• Splenectomy may be performed
• Bone marrow transplant can be curative
Where is the gene coding for beta Thalassaemia found?
Chromosome 11
What are the 2 types of gene defects that can occur in the beta globin gene?
Abnormal copies = can retain some function
Deletion genes = no fucntiin
What are the 3 types of beta Thalassaemia?
• Thalassaemia minor
• Thalassaemia intermedia
• Thalassaemia major
What types of genes do people with Thalassaemia minor/trait have?
Carries
Have 1 abnormal and 1 normal gene
What are the symptoms of Thalassaemia minor/trait?
Mild microcytic anaemia
What type of gene copies do people with Thalassaemia intermedia carry?
2 abnormal copies either:
• Two defective genes
• One defective gene and one deletion gene
What are the symptoms of Thalassaemia intermedia?
Significant microcytic anaemia
What is the management of Thalassaemia intermedia? (3)
Monitoring
Blood transfusions
Iron chelation to prevent iron overload
What gene types do people with Thalassaemia major carry?
Homozygous for the deletion genes
No functioning beta globin chains
What does Thalassaemia major present with? (2)
Severe anaemia
Failure to thrive in early childhood
What happens to bone marrow in Thalassaemia major?
The bone marrow is under so much strain to produce extra red blood cells to compensate for the chronic anaemia that it expands enough to increase the risk of fractures and change the patient’s appearance.
