The first _____ was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Clinical gene therapy
Option (1) Chemotherapy — Incorrect. Chemotherapy is the use of drugs that kill cancer cells. It does not correct a faulty gene.
Option (2) Radioactive therapy — Incorrect. Radiotherapy uses radiation to kill tumour cells. Like chemotherapy, it is a treatment for cancer, not for a missing gene.
Option (3) Clinical gene therapy — Correct. Gene therapy puts a normal gene into the patient’s cells to take over from the missing one. For ADA deficiency, lymphocytes from the patient’s blood are grown outside the body. A working ADA cDNA is put into them with a retroviral vector, and they are returned to the patient.
Option (4) Stem cell technology — Incorrect. This technology uses unspecialised cells that can form many kinds of cells. Their use replaces damaged cells; it does not put a normal gene into the patient’s own cells.
NCERT Extract:
Gene Therapy – …
