Gene Therapy and ADA Deficiency — NEET Biology

Which of the following statements are NOT correct regarding gene therapy and its applications? S1: Gene therapy is a collection of methods that allows the correction of a gene defect diagnosed in a child or embryo by inserting genes into a person's cells and tissues. S2: The first clinical gene therapy was successfully administered in 1990 to a 4-year-old girl suffering from adenosine deaminase (ADA) deficiency. S3: For ADA deficiency, periodic infusion of genetically engineered lymphocytes provides a permanent cure if the gene isolated from marrow cells is introduced at early embryonic stages. S4: A functional ADA cDNA is typically introduced into lymphocytes using a retroviral vector after the lymphocytes are grown in culture outside the patient's body. S5: Enzyme replacement therapy and bone marrow transplantation are completely curative and permanent solutions for ADA deficiency, making further gene therapy unnecessary.