Adenosine deaminase deficiency

Also known as ADA deficiency. A specific enzyme deficiency known to cause an autosomal recessive form of severe combined immunodeficiency disease (SCID). Those afflicted with ADA deficiency may have various skeletal abnormalities in addition to a severe reduction in B and T lymphocytes and natural killer (NK) cells, which would result in death from opportunistic infection if left untreated. Enzyme replacement therapy and bone marrow transplants have been used as treatment.