Which of the following is correct about ADA ?

Options

A. ADA is crucial for immune system to function
B. In the absence of this enzyme, purine metabolism is disturbed and T-cells fail to function
C. ADA deficiency is caused by deletion of the gene for ADA
D. All

Answer

To determine which statements about ADA (adenosine deaminase) are correct, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding ADA**:
- ADA stands for adenosine deaminase, which is an enzyme that plays a crucial role in the immune system. Its primary function is to help in the metabolism of purines, which are essential for the proper functioning of T cells, a type of white blood cell involved in immune responses.

2. **Evaluating the Statements**:
- **Statement 1**: "ADA is crucial for the immune system to function."
- This statement is correct because ADA is essential for the proper functioning of T cells, which are vital for the immune response.

- **Statement 2**: "In the absence of the enzyme, purine metabolism is disturbed, affecting T cell function."
- This statement is also correct. Without ADA, there is a buildup of toxic metabolites, which can impair T cell function and lead to immune deficiencies.

- **Statement 3**: "ADA deficiency is caused by deletion of genes of ADA."
- This statement is true as well. ADA deficiency can result from mutations or deletions in the ADA gene, leading to severe combined immunodeficiency (SCID).

3. **Conclusion**:
- Since all three statements about ADA are correct, the answer to the question is that all of the above statements are true.

### Final Answer:
All of the above statements about ADA are correct.

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