Adenosine deaminase deficiency
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Adenosine deaminase deficiency, or ADA deficiency, is an inherited immunodeficiency syndrome accounting for about 25% of all cases of severe combined immunodeficiency (SCID).
This disease is due to a lack of the enzyme adenosine deaminase coded for by a gene on chromosome 20. There is an accumulation of dATP, which causes an increase in S-adenosylhomocysteine; both substances are toxic to immature lymphoid cells, so fail to reach maturity. As a result, the immune system of the afflicted person is severely compromised or completely lacking.
The enzyme adenosine deaminase is important for purine metabolism.
Treatment
- bone marrow transplant
- gene therapy (efforts halted due to increased incidence of leukemia)
- ADA enzyme in PEG vehicle