Severe Combined Immune Deficiency (SCID), ADA Type

ADA deficiency is associated with an autosomal recessive form of severe combined immune deficiency (SCID) in which B, T, and NK cells are deficient. Bacterial, viral and fungal infections are common and often life-threatening, but there is a wide range of severity and age of onset. Diminished red cell adenosine deaminase activity is diagnostic, correlating with deoxyadenosine toxicity in lymphocytes. Enzyme replacement, bone marrow/stem cell transplantation, and gene therapy have been used successfully for treatment.