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Thalassemia |
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Thalassemia (American English) (or Thalassaemia in British English) is an inherited disease of the red blood cells, classified as a hemoglobinopathy. The genetic defect results in synthesis of an abnormal hemoglobin molecule. The blood cells are vulnerable to mechanical injury and die easily. To survive, many people with thalassaemia need blood transfusions at regular intervals.
Being a carrier of the disease confers a degree of protection against malaria, and is quite common among people from Italian or Greek origin, since malaria was widespread in those countries at one time. In that respect it resembles another genetic disorder, sickle-cell disease
The thalassemias are classified according to which chain of the globin molecule is affected: in a thalassemia, the production of a globin is deficient, while in ÃY thalassemia the production of ÃY globin is defective. Thalassemia produces a deficiency of a or ÃY globin, unlike sickle-cell disease which produces a specific mutant form of ÃY globin.
Both a and ÃY thalassemia are inherited in an autosomal recessive fashion. Both parents must be carriers in order for a child to be affected. If both parents carry a hemoglobinopathy trait, there is a 25% chance with each pregnancy for an affected child. Genetic counseling and genetic testing is recommended for families that carry a thalassemia trait.
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