ADA deficiency: It refers to the deficiency of enzyme adenosine deaminase (ADA) caused by the deletion of the gene coding for this enzyme. This enzyme is crucial for the immune system to function.
Gene therapy: Lymphocytes from the blood of the patient are grown in a culture outside the body. A functional ADA cDNA is then introduced using a retroviral vector into the lymphocytes, which in turn are then returned to the patient. However, as these cells are not immortal, the patient requires periodic infusion of such genetically engineered lymphocytes.
