The first clinical gene therapy was given for the deficiency of which of the following enzymes ?

Options

A. a denosine deaminase (ADA) deficiency
B. tyrosinase deficiency
C. homogentisix acid oxidase deficiency
D. phenylalanine hydroxylase deficiency

Answer

To solve the question regarding the first clinical gene therapy given for the deficiency of a specific enzyme, we can follow these steps:

### Step 1: Identify the Enzymes Listed
The question provides four options related to enzyme deficiencies:
1. ADA (Adenosine Deaminase) deficiency
2. Tyrosine deficiency
3. Homogentisate oxidase deficiency
4. Phenylalanine hydroxylase deficiency

### Step 2: Understand Clinical Gene Therapy
Clinical gene therapy involves the introduction, removal, or alteration of genetic material within a patient's cells to treat a disease. It has been used to address various genetic disorders, particularly those caused by enzyme deficiencies.

### Step 3: Research Historical Context
The first successful clinical gene therapy was performed in 1990. It was aimed at treating a specific genetic disorder caused by the deficiency of a particular enzyme.

### Step 4: Identify the Correct Enzyme
Among the listed options, ADA deficiency is known to be the first condition treated with gene therapy. The patient was a 4-year-old girl named Ashanthi DeSilva, who suffered from severe combined immunodeficiency (SCID) due to ADA deficiency.

### Step 5: Conclude the Answer
Based on the historical context and the information gathered, the correct answer to the question is:
**ADA deficiency** (Option 1).

### Final Answer
The first clinical gene therapy was given for the deficiency of **ADA (Adenosine Deaminase)**.

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