2: B-Thalasemia Flashcards
In which populations is B thalasemia more common
Medeteranian
what is the inheritance of B thalasemia
Autosomal recessive
what is adult Hb made up of
2a and 2b chains
where is B-globin gene located
Chromosome 11
what can mutations cause
Mutations cause either a deficiency in b chain (B+) or absence of b chain (B0).
what does deficiency in B-chains cause
Lack of b chains cause alpha chains to aggregate together which can damage RBC membranes causing haemolysis - resulting in Hb accumulating in circulation where it is converted to unconjugated bilirubin and iron
what is B thalasemia minor
one mutated copy (that reduces B cells) and one normal copy
What is B thalasemia minor known as
carrier state
How does B thalasemia minor present clinically
well-tolerated anaemia
may be exacerbated by pregnancy
what is B thalasemia intermediate
co-inheritance of mutations that reduce B chain
how does B thalasemia intermedia present
intermediate state with moderate anaemia - does not require transfusions
what is B thalasemia major
abnormality in both B globin genes
how does B thalasemia major present clinically
Severe anaemia and FTT in first-year
what can occur in B thalasemia major and why
Frontal bossing - due to extra-medullary haematopoiesis and hepatosplenomegaly
what does B thalasemia major cause
life long blood transfusions that can lead to cardiac and renal toxicity and endocrine failure
