BPT Haematology

Question 1

Beta thalassaemia major

Answer 1

Homozygous beta global chain defect. Excess alpha chains combine with available alpha / delta / gamma chains.

Bº: no normal beta chains; increased HbA2 and HbF
B+: reduced beta chain production; increased HbA2 and HbF, reduced amounts of HbA

Severe anaemia after 3-6mo, FTT and recurrent infections, extra medullary haematopoeisis

Question 2

Beta thalassaemia minor

Answer 2

Heterozygous defect in beta globin chain production. Increased HbA2, HbF (usually 2% /

Mild or absent anaemia, microcytosis; normal ferritin and iron

Question 3

Alpha thalassaemia

Answer 3

Each alpha global chain has 2 genes on Ch.16; each gene has 2 alleles.

Silent carrier : 1 gene deletion, normal RBCs

Alpha-Thal trait, 2 gene deletion(-/- + a/a, or -/a + -/a): microcytosis, normal iron studies.

HbH disease 3 gene deletion (HbA, HbA2, HbH, : moderate - severe symptoms, jaundice / HA / splenomegaly;

Hb Barts 4 gene deletion, (gamma x 4): hydrops + death