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Sickle cell trait patients do not have manifestations of sickle cell disease because:


  1. 50% HbS is required for occurrence of sickling.
  2. HbA prevents sickling.
  3. 50% sickles.
  4. HbA prevents polymerization of HbS.

1 comment:

  1. 1. 50% HbS required for sickling.

    Sickle cell trait (or sicklemia) describes a condition in which a person has one abnormal allele of the hemoglobin beta gene (is heterozygous), but does not display the severe symptoms of sickle cell disease that occur in a person who has two copies of that allele (is homozygous). Those who are heterozygous for the sickle cell allele produce both normal and abnormal hemoglobin (the two alleles are co-dominant). Sickle cell disease is a blood disorder in which the body produces an abnormal type of the oxygen-carrying substance hemoglobin in the red blood cells. Sickling and sickle cell disease also confer some resistance to malaria parasitization of red blood cells, so that individuals with sickle-cell trait (heterozygotes) have a selective advantage in some environments.

    A person with sickle cell trait inherits one normal gene and one abnormal gene encoding hemoglobin S (hemoglobin genotype AS).

    Sickle cell trait is a hemoglobin genotype AS is generally regarded as a benign condition. However, individuals with sickle cell trait may have rare complications.

    Established associations:

    1. Renal medullary carcinoma, a cancer affecting the kidney, is a very rare complication seen in patients with sickle cell trait.

    2. hematuria
    3. renal papillary necrosis
    4. hyposthenuria
    5. splenic infarcts at high altitude.

    6. urinary tract infection

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