Thalassaemia

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 $\beta$
• 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