The genetic defect-Adenosine Deaminase deficiency may be cured permanently by

Options

A. periodic infusion of genetically engineered lymphocytes having functional ADA C-DNA
B. administering adenosine deaminase activators
C. introducing bone marrow cells producing ADA into cells at early embryonic stages
D. enzyme replacement therapy

Answer

### Step-by-Step Solution

1. **Understanding Adenosine Deaminase Deficiency**:
- Adenosine deaminase (ADA) is an enzyme produced by the ADA gene.
- This enzyme plays a crucial role in the immune system, particularly in lymphocytes, which are produced in the bone marrow.

2. **Identifying the Genetic Disorder**:
- The deficiency of the ADA enzyme leads to a genetic disorder known as Severe Combined Immunodeficiency (SCID).
- SCID is characterized by a life-threatening syndrome of recurrent infections due to a compromised immune system.

3. **Exploring Treatment Options**:
- The question asks how this deficiency can be cured permanently.
- Several treatment options can be considered, including periodic infusion of genetically engineered lymphocytes, enzyme replacement therapy, and bone marrow transplantation.

4. **Evaluating Treatment Options**:
- **Option A**: Periodic infusion of genetically engineered lymphocytes – This method requires ongoing treatment and is not a permanent solution.
- **Option B**: Administering adenosine deaminase activators – This does not address the root cause of the deficiency and is not a permanent cure.
- **Option C**: Introducing bone marrow cells producing ADA into cells at early embryonic stages – This option is a permanent solution as it targets the root cause by ensuring the production of functional ADA from the start.
- **Option D**: Enzyme replacement therapy – Similar to option A, this is not a permanent solution as it requires continuous administration.

5. **Conclusion**:
- The best option for permanently curing adenosine deaminase deficiency is **Option C: Introducing the bone marrow cells producing the ADA into cells at early embryonic stages**. This method ensures that the ADA enzyme is produced effectively, addressing the deficiency at its source.