The Adenosine deaminase deficiency results into:

Adenosine deaminase enzyme deficiency causes SCID (Severe Combined Immunodeficiency). ADA enzyme is required for the survival of T-lymphocytes. Thus, deficiency of Adenosine deaminase enzyme causes dysfunction of immune system, due to loss of cell-mediated immunity.

The main symptoms of ADA deficiency are pneumonia, chronic diarrhea, and widespread skin rashes. Affected children also grow much more slowly than healthy children and some have developmental delay.