Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Gene therapy involving the introduction of functional ADA cDNA into lymphocytes provides a permanent cure for Adenosine deaminase (ADA) deficiency. Reason (R): The genetically engineered lymphocytes introduced into the patient are not immortal, hence the patient requires periodic infusion of such c

Step-by-step solution

According to NCERT, gene therapy for ADA deficiency involves extracting lymphocytes from the patient's blood, introducing a functional ADA cDNA into them using a retroviral vector, and returning them to the patient. However, because these genetically engineered lymphocytes are not immortal, the patient requires periodic infusion of such cells. Therefore, this somatic cell gene therapy approach does not provide a permanent cure. A permanent cure is only possible if the gene isolated from marrow cells producing ADA i