Thalassaemia Flashcards
Synthesis of haemoglobin occurs during…?
Development of RBC
Begins in pro-erythroblast:
- 65% erythroblast stage
- 35% reticulocyte stage
What is the structure of haemoglobin?
Haem (synthesised in mitochondria)
Globin (synthesised in ribosomes)
Slide 6 [pic]
Describe the synthesis of haemoglobin
Slide 7 [pic]
What is the structure of haem?
Combination of protoporphyrin ring with central iron atom (ferroprotoporphyrin)
Iron usually in ferrous form (Fe2+)
Able to combine reversibly with oxygen
Also contained in other proteins (e.g. myoglobin, cytochromes, peroxidases, catalses, tryptophan)
Same in all types of Hb
Slide 9 [pic]
Where is haem synthesised?
Mainly in mitochondria which contain the enzyme ALAS
Describe the structure of globin
Eight functional globin chains, arranged in two clusters:
- beta cluster (beta, gamma, delta and epsilon globin genes) on the short arm of chromosome 11
- alpha cluster (alpha and zita goblin genes) on the short arm of chromosome 16
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What is the structure of haemoglobin A?
Slide 13
What is the structure of haemoglobin A2?
Slide 13
What is the structure of haemoglobin F?
Slide 13
What is the primary structure of globin?
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What is the secondary structure of globin?
Slide 15
What is the tertiary structure of globin?
Slide 15
The normal position of the Hb-oxygen dissociation curve depends on…?
Slide 19
What happens when the Hb-oxygen dissociation curve shifts to the right?
Slide 20
What happens when the Hb-oxygen dissociation curve shifts to the left?
Slide 20
What are haemoglobinopathies due to?
Structural variants of haemoglobin or defects in globin chain synthesis (thalassaemia)
Genetic disorders characterised by a defect of globin chain synthesis
Most common inherited single gene disorder worldwide
What is beta thalassaemia?
Slide 27
Presents usually about 3 months
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How is beta thalassaemia diagnosed in the lab?
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What is thalassaemia major?
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What is the clinical presentation of thalassaemia major?
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What are the clinical features of beta thalassaemia?
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What are other complications of beta thalassaemia?
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What are the different treatments for thalassaemia major?
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Describe the treatment of thalassaemia using transfusions
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How is infection managed during the treatment of thalassaemia?
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Describe the treatment of thalassaemia using iron chelation therapy
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How is iron overload monitored?
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What is HbE beta thalassaemia?
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What is alpha thalassaemia?
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What is a thalassaemia carrier?
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What are the problems associated with treatment of thalassaemia in developing countries?
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Describe the screening and prevention of thalassaemia
Screening and prevention
