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Important presentation about Thalassemia (Microcytic Anemia)

  • Definition: hereditary underproduction of either the alpha or beta globin chains of the hemoglobin A  resulting in a  microcytic anemia.
  • Beta thalassemias are due to mutations in the HBB gene on chromosome 11.
  • The α thalassemias involve the genes HBA1 and HBA2 on chromosome 16.

Beta- Thalassemia
  • The β-globin mutations associated with β-thalassemia fall into two categories: 
  • (1) β0, in which no β-globin chains are produced; and 
  • (2) β+, in which there is reduced (but detectable) β-globin synthesis
  • Individuals inheriting one abnormal allele have thalassemia minor or thalassemia trait, which is asymptomatic or mildly symptomatic. 
  • Most individuals inheriting any two β0 and β+ alleles have β-thalassemia major; 
  • occasionally, individuals inheriting two β+ alleles have a milder disease termed β-thalassemia intermedia.

Alpha-Thalassemias
  • alpha- thalassemias result in decreased alpha-globin production, therefore fewer alpha-globin chains are produced, resulting in an excess of β chains in adults and excess γ chains in newborns.The excess β chains form unstable tetramers (called Hemoglobin H or HbH of 4 beta chains) which have abnormal . The severity of the alpha- thalassemias is correlated with the number of affected alpha-globin genes.  
  •  alpha0 thalassaemias, where there is lots of gama4 but no alpha-globins at all (referred to as Hb Barts), often result in still birth.
  • The most severe form of alpha thalassemia major causes stillbirth.
  • Other symptoms can include:
  • Bone deformities in the face
  • Fatigue
  • Growth failure
  • Shortness of breath
  • splenomegaly
Diagnostic features of beta-thalassaemia

Dx
  • A physical exam may reveal a swollen (enlarged) spleen.
  • Blood test:
  • Red blood cells will appear small and abnormally shaped when looked at under a microscope.
  • A complete blood count (CBC) reveals anemia.
  • A test called hemoglobin electrophoresis shows the presence of an abnormal form of hemoglobin

Rx
  • Treatment for thalassemia major often involves regular blood transfusions and folate supplements.
  • If you receive blood transfusions, you should not take iron supplements. Doing so can cause a high amount of iron to build up in the body, which can be harmful.
  • Persons who receive significant numbers of blood transfusions need a treatment called chelation therapy to remove excess iron from the body.
  • Bone marrow transplant may help treat the disease in some patients, especially children.
  • Hydrops fetalis: none available 
  • Haemoglobin H: no specific therapy required; avoid iron therapy; folic acid if necessary 
TREATMENT OF BETA-THALASSAEMIA MAJOR