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  1. Disorder of reduced Hb synthesis. If synthesis of a, chains is suppressed level of all three normal Hb i.e A, A2 land are reduced → alpha thalassemia. Q
  2. If beta chains are suppressed because of mutation in beta gene than production of adult hemoglobin is suppressed Beta Thalassemia. Q 

β Thalassemia

  1. β chain production is either totally, partially or minimally depressed depending upon the mutation.
  2. The genes are designated as β° and β+ respectively and are arranged on short arm of chromosome 11. Since β chain synthesis is reduced, the excess of a chains produces a tetramers which get precipitated in red cells. These cells get lysed with in the bone marrow before being released as reticulocytes.


Lab Investigation

  1. Hb-2-6 gm%
  2. PCV - decreased
  3. MCV / MCH/ MCHC decreased
  4. PBF- anisocytosis, poikilocytosisQ
  5. Variable number of target and tear drop cellsQ
  6. Marked basophilic stippling and variable polychromasia. Q
  7. Howell Jolley bodies and Heinz bodies may be seen.
  8. Serum iron levels increase
  9. S. Ferritin increase
  10. Hb -F increase Hb- A2 increase
  11. Osmotic fragility is decreasedQ 

Radiological changes in Thalassemia

  1. Earliest bony change occurs in the small bones of the hands which show a rectangular appearance
    Medullary portion is widened and cortex thinned out.
  2. Diploid spaces in the skull are widened: Hair on end appearance in X-ray film of the skull.
    Pneumatization of the sinuses is delayed. 

Treatment-New therapeutic approaches

  1. Bone marrow transplantation
  2. Gene therapy
  3. Blood transfusion
  4. Chelation therapy
    1. Desferrioxamine
    2. Defer prone: Oral preparation.
  5. Splenectomy- recommended when transfusion requirement exceeds 250ml/ kg / yr of packed red cells. Q
  6. Avoid iron containing food.
  7. Drugs
    1. Hydroxyurea
    2. Butyrate salts 

Prenatal diagnosis

  1. Can be made from fetal blood by determining the p versus a chain ratio. A ratio of less than 0.025 is suggestive of thalassemia major and need of medical termination of pregnancy
  2. Carrier detection is done by HbA2 levelQ
    If>3.5% indicates carrier. 

α Thalassemia

  1. Deletion alpha globin genes accounts for most of these abnormalities
  2. Deletion of a single alpha gene produce silent carriers
  3. Deletion of two alpha globin gene exhibit feature of alpha thalassemia trait.
  4. Deletion of three alpha globin gene associated with thalassemia intermedia like syndrome, Hb H disease.
  5. Deletion of all four alpha- globin genes is accompanied by a total absence of alpha chain synthesis because HbF.
  6. A and A2 all contain alpha chains none of these hemoglobin is affected infants.
  7. γ4 has a high oxygen affinity and there fore can not transport oxygen to the issue these infants are severally hypoxic.
  8. Their RBCs also contain small amount of the Portland Hb which functions as an effective oxygen transporter.
  9. Most of these infants are stillborn and most who are born alive die with in few hours.
  10. These infants are severely hydropic with congestive heart failure and massive generated edema 


  1. α silent carrier  -, α/α, α
  2. α Trait              -, α/-, α or -, - / α, α
  3. Hb H disease.   -, α / - -
  4. α Hydrops fetals -, - / -, -
    [Hb Bart γ4]

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