Adenosine deaminase deficiency

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

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