This deficiency results in an accumulation of deoxyadenosine, which, in turn, leads to:

a buildup of dATP in all cells, which inhibits ribonucleotide reductase and prevents DNA synthesis, so cells are unable to divide. Since developing T cells and B cells are some of the most mitotically active cells, they are highly susceptible to this condition. an increase in S-adenosylhomocysteine since the enzyme adenosine deaminase is important in the purine salvage pathway; both substances are toxic to immature lymphocytes, which thus fail to mature.Because T cells undergo proliferation and development in the thymus, affected individuals typically have a small, underdeveloped thymus. As a result, the immune system is severely compromised or completely lacking. Diagnosis
The diagnosis is based on clinical features, with a concomitant decreased blood adenosine deaminase level supporting the diagnosis. Treatment
Treatments include:
bone marrow transplant
ADA enzyme in PEG vehicle

Gene therapy
In September 1990, the first gene therapy to combat this disease was performed by Dr. William French Anderson on a four-year-old girl, Ashanti DeSilva, at the National Institutes of Health, Bethesda, Maryland, U.S.A. In April 2016 the Committee for Medicinal Products for Human Use of the European Medicines Agency endorsed and recommended for approval a stem cell gene therapy called Strimvelis, for children with ADA-SCID for whom no matching bone marrow donor is available. History
ADA deficiency was discovered in 1972 by Eloise Giblett, a professor at the University of Washington. The ADA gene was used as a marker for bone marrow transplants. A lack of ADA activity was discovered by Giblett in an immunocompromised transplant candidate.
While a prospective comparison of VAC versus BEP has not been performed, in well-staged patients with completely resected tumors, relapse is essentially unheard of following platinum-based chemotherapy. However, the disease will recur in about 25% of well-staged patients treated with 6 months of VAC. See also
Teratoma
Ovarian Cancer
Germ Cell Tumor

References
External links

Immature teratoma entry in the public domain NCI Dictionary of Cancer Terms This article incorporates public domain material from Dictionary of Cancer Terms. U.S. National Cancer Institute.