Thalassemia

July 2017


Definition


The term thalassemia regroups several hereditary blood diseases, especially in regards to hemoglobin, which becomes deficient in red blood cells. Due to a deficiency in one of the four chains of hemoglobin, thalassemia most commonly affects certain populations, including Mediterranean countries and the Far East. There are several types of thalassemia: beta thalassemia, or Cooley's anemia, in which both genes are affected (called homozygous thalassemia), beta-thalassemia, or Rietti Greppi-Micheli disease, in which one of the two genes is affected (heterozygous), and alpha-thalassemia, which is fatal before birth in its homozygous form but benign in its heterozygous form. In all three forms, normal hemoglobin is secreted in insufficient quantities. Other forms also exist, where abnormal hemoglobin is synthesized. The common denominator of all these thalassemias is that they cause chronic anemia and its complications, including heart failure. If untreated in its major forms, the disease can progress to death.

Symptoms


In the case of major thalassemia:
  • Severe anemia in infancy;
  • discoloration of the skin;
  • increase in the size of the liver and spleen;
  • skull and face abnormalities;
  • bone growth disorders.

In the case of heterozygous thalassemia:
  • slight increase in the spleen;
  • moderate anemia;
  • sometimes, a slightly yellowing of the skin.

For alpha-thalassemia:
  • Symptoms vary depending on the number of genes affected, ranging from the death of the fetus to the complete absence of symptoms.

Diagnosis


For homozygous thalassemia, in addition to physical criteria, laboratory testing allows for a diagnosis highlighting severe anemia, sometimes less than 6 g per liter. In all cases, necessary examinations include a blood analysis and hemoglobin electrophoresis, which identifies the types of hemoglobin present and its distribution in the blood. Genetic analysis is also possible.

Treatment


In the case of a homozygous thalassemia, repeated blood transfusions are needed at an early age. Due to the increase of iron in the blood, drugs to partially neutralize the latter are used: iron chelators. These treatments are used to control the disease, but the only curative treatment is a bone marrow transplant.

Prevention


The only mode of prevention is genetic counseling based on relatives who already have thalassemia. Before birth, techniques for mutations or hemoglobin electrophoresis in the fetus are possible.

Related

Original article published by . Translated by Jeff. Latest update on July 23, 2013 at 12:33 PM by Jeff.
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