Which one of the following can be used as a permanent ewe for ADA deficiency?

Options

A. Bone marrow transplantation upon detection of disorder in adult
B. Enzyme replacement therapy at any point 'in life
C. Both (1) & (2)
D. Gene therapy at early embryonic stages

Answer

To solve the question regarding a permanent solution for ADA (Adenosine Deaminase) deficiency, we can follow these steps:

### Step-by-Step Solution:

1. **Understand ADA Deficiency**:
- ADA stands for Adenosine Deaminase, which is an enzyme crucial for the immune system. Its deficiency leads to severe combined immunodeficiency (SCID) due to the accumulation of toxic metabolites that affect lymphocyte maturation.

2. **Evaluate Treatment Options**:
- The question provides several options for treating ADA deficiency. We need to assess each option to determine which one offers a permanent solution.

3. **Option A - Bone Marrow Transplantation**:
- Bone marrow transplantation can help in some cases, but it is not a permanent solution for ADA deficiency, especially if done in adults. This is because lymphocytes have a short lifespan, and the treatment needs to be administered early.

4. **Option B - Enzyme Replacement Therapy**:
- Enzyme replacement therapy can provide temporary relief but does not offer a permanent solution. The body will still lack the necessary enzyme production.

5. **Option C - Both A and B**:
- Since both options A and B are not permanent solutions, this option is also incorrect.

6. **Option D - Gene Therapy at Early Embryonic Stage**:
- Gene therapy involves correcting the genetic defect responsible for ADA deficiency. Administering this therapy at an early embryonic stage can lead to a permanent solution as it allows for the proper development of the immune system.

7. **Conclusion**:
- The best and permanent solution for ADA deficiency is gene therapy at an early embryonic stage. Therefore, the correct answer is option D.

### Final Answer:
**Option D - Gene therapy at early embryonic stage.**