Phenylketonuria is genetic disorder caused by a defect in metabolism of

Options

A. Fatty acids
B. Polysaccharide
C. Amino acids
D. Vitamins

Answer

**Step-by-Step Solution:**

1. **Understanding Phenylketonuria (PKU)**:
- Phenylketonuria is a genetic disorder that falls under the category of inborn errors of metabolism. It is primarily characterized by the body's inability to properly metabolize phenylalanine, an amino acid.

2. **Identifying the Cause**:
- The disorder is caused by a defect in a specific gene that leads to a deficiency in the enzyme phenylalanine hydroxylase. This enzyme is crucial for converting phenylalanine into another amino acid, tyrosine.

3. **Consequences of the Deficiency**:
- Due to the deficiency of phenylalanine hydroxylase, phenylalanine accumulates in the blood. This accumulation can lead to toxic effects, including intellectual disabilities and behavioral problems.

4. **Classifying the Disorder**:
- PKU is classified as an autosomal recessive disorder, meaning that an individual must inherit two copies of the defective gene (one from each parent) to express the disorder.

5. **Answering the Question**:
- The question asks about the metabolic defect that causes phenylketonuria. Since the disorder is related to the metabolism of phenylalanine, which is an amino acid, the correct answer is that phenylketonuria is caused by a defect in the metabolism of amino acids.

**Final Answer**: Phenylketonuria is a genetic disorder caused by a defect in the metabolism of **amino acids**.

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