Question

Assertion (A): A patient of ADA-deficiency requires periodic or repeated infusion of genetically-engineered lymphocytes.
Reason (R): Lymphocytes are not immortal, but have life span.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
• C. (A) is true, but (R) is false.
• D. (A) is false, but (R) is true.

Hint:

In ADA-deficiency, periodic infusion of modified lymphocytes is needed due to their limited lifespan unless permanent gene correction is done in stem cells.

Answer 1

The Correct Option is A

Step 1: ADA-deficiency leads to immunodeficiency and one treatment is gene therapy using engineered lymphocytes. So, Assertion (A) is true.
Step 2: Since lymphocytes have limited lifespan, the treatment must be repeated—making Reason (R) true.
Step 3: As the short life of lymphocytes explains the need for repeated infusion, (R) correctly explains (A).
Thus, both (A) and (R) are true and (R) is the correct explanation of (A).