Adenosine Deaminase(ADA) Deficiency Cause Severe Combined Immuno-Deficiency Disorder(SCID)
- Adenosine deaminase deficiency (ADA deficiency) is a rare genetic disorder that leads to a severe combined immunodeficiency disorder
* SCID is a group of disorders characterized by a profound impairment of the immune system, leaving affected individuals highly susceptible to infections. SIGN AND SYMPTOMS:
- Pneumonia
- Chronic diarrhoea
- Wide spread skin rashes
- Jaundice
- Candidiasis
ADA deficiency
- ADA enzyme plays a major role in degradation of purine nucleotides to uric acid
- It is associated with severe immunodeficiency where both T and B cells are deficient.
- It is an inherited autosomal recessive disease.
- ADA deficiency leads to accumulation of Adenosine and dATP;this would inhibit further production of precursors for DNA synthesis especially dCTP.
- Lymphocytes usually contains high quantity of ADA.Therefore, ADA deficiency is mainly manifested as reduced lymphocytes.This leads to impaired cellular and humoral immunity.
- ADA deficiency causes the accumulation of adenosine which increases the dATP level which will inhibit ribonuclotide reductase which eventually decreases dGTP, dCTP, dTTP levels and prevents DNA synthesis, so cells are unable to divide.
- Since immature lymphocytes are most mitotically active cells, they are highly susceptible to this condition.
- As a result, the immune system is severely compromised or completely lacking and thus causes severe combined immunodeficiency disorder