What is the permanent cure of adenosine deaminase (ADA) deficiency in children ?

Options

A. Bone marrow transplantation
B. Enzyme replacement therapy in which functional ADA is given to patient by injection
C. Infusion of genetically engineered lymphocytes (in which functional ADA-cDNA is introduced) into the patient's blood
D. Introduction of gene isolated from the bone marrow cells which produce ADA, into the cells of the patient at early embryonic stages

Answer

### Step-by-Step Solution:

1. **Understanding ADA Deficiency**: Adenosine deaminase (ADA) deficiency is a genetic disorder that leads to severe immunodeficiency in children. It is caused by a lack of the enzyme adenosine deaminase, which is crucial for the immune system.

2. **Temporary Treatments**: There are two main temporary methods for treating ADA deficiency:
- **Bone Marrow Transplantation**: This involves transplanting healthy bone marrow from a donor to the patient, which can provide the necessary ADA enzyme.
- **Enzyme Replacement Therapy**: In this method, the functional ADA enzyme is administered to the patient through injections.

3. **Permanent Cure**: The permanent cure for ADA deficiency involves gene therapy. This method includes:
- **Gene Introduction**: A gene that encodes for the ADA enzyme is isolated from healthy bone marrow cells.
- **Delivery to Patient Cells**: This gene is then introduced into the patient's cells, ideally at early embryonic stages, allowing the patient's body to produce the ADA enzyme naturally.

4. **Conclusion**: Among the options provided, the introduction of the ADA gene isolated from bone marrow cells into the patient's cells at early embryonic stages is the only permanent cure for ADA deficiency.

### Final Answer:
The permanent cure for adenosine deaminase (ADA) deficiency in children is the introduction of a gene isolated from bone marrow cells that produce ADA into the cells of the patient at early embryonic stages.

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