Change in globin gene expression leads to reduced rate of synthesis of normal globin chains. Pathology due to excess of unaffected chain in blood.
(\alpha)-thalassaemia
- Recessive disorder - 4 genes in control. Pathology from excess
- Hb Barts (all 4 genes (a^0)) - hydrops fetalis incompatible with life
(\beta)-thalassaemia
- Similar to alpha - microcytic hypochromic RBCs
Trait - Hb level normal or only slighly reduced - no clinical probs
Intermedia - no absolute requirement for transfusions to survive. Clinical picture v dependant on genetics
Major - severe Anaemia, lots of abnormal nucleated RBCs clinical features due to severe Anaemia. Hair on end skull
Need blood but causes Fe toxicity so iron chelation needed too