Adenosine deaminase (ADA) catalyzes adenosine degradation. Lack of this enzyme leads to the accumulation of toxic metabolites causing severe combined immunodeficiency (ADA-SCID), an autosomal recessive disorder. Differentiation and function of T cells, B cells, and natural killer cells are impaired in ADA-SCID patients leading to recurrent infections. Gene therapies for ADA-SCID were reported to correct the metabolic defect and restore the deficient immune function.
