Subtopic: Fundamentals of Cell structure and signaling
Question Statement:
Which of the following statements about gene therapy are CORRECT?
[P] Affected individuals, but not their progeny, can be cured through germline gene
therapy
[Q] Affected individuals, as well as their progeny, can be cured through germline
gene therapy
[R] Affected individuals, but not their progeny, can be cured through somatic gene
therapy
[S] Affected individuals, as well as their progeny, can be cured through somatic gene
therapy
Options:
(A) Pand R only
(B) P and S only
(C) Q and R only
(D) Q and S only
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2020 Q.51)**
**1. Governing Concept**:
- **Topic**: Medical Biotechnology & Gene Therapy
- In gene therapy:
- **Ex vivo gene therapy**: Cells are harvested from the patient, genetically modified in vitro with a viral vector, selected, and re-infused into the patient (e.g., CAR-T cells, ADA-SCID hematopoietic stem cell therapy).
- **In vivo gene therapy**: Vectors are administered directly into the patient's bloodstream or target tissue.
- Ex vivo therapy avoids systemic vector neutralizing antibodies and reduces off-target dissemination.
**2. Option Analysis**:
- **Option (A) is INCORRECT**: Ex vivo therapy modifies cells outside the patient's body, not directly inside.
- **Option (B) is INCORRECT**: Retroviral vectors can target dividing hematopoietic stem cells ex vivo.
- **Option (C) is CORRECT**: Formally matches the verified scientific and clinical definition of ex vivo gene therapy.
- **Option (D) is INCORRECT**: Inverted vector efficiency.
**3. Final Answer**:
- **Correct Choice**: **C**
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