copy of the adenosine deaminase gene into those cells, and reintroduced the modified cells into the body’s circulation. The modified cells then could produce sufficient adenosine deaminase to prevent deoxyadenosine accumulation. This kind of gene therapy is called somatic gene therapy.3 It does not cure the disease, however, because the modified blood cells have only a relatively short life span and are continuously replaced by new, defective blood cells. Therefore, the patients require repeated, lifelong treatments.
