Certain diseases are caused by enzyme defiencies. Explain giving one example.

Explanation

### Step-by-Step Solution:

1. **Understanding Enzyme Deficiency**: Enzyme deficiencies occur when the body does not produce enough of a certain enzyme or when the enzyme produced is not functional. Enzymes are crucial for catalyzing biochemical reactions, and their absence can lead to the accumulation of substrates and a deficiency of products.

2. **Causes of Enzyme Deficiency**: Enzyme deficiencies can be caused by various factors, including genetic mutations, which can lead to inherited metabolic disorders. These mutations can prevent the synthesis of a specific enzyme or result in the production of a non-functional enzyme.

3. **Example of an Enzyme Deficiency Disease**: One well-known example of a disease caused by enzyme deficiency is Phenylketonuria (PKU). PKU is a genetic disorder caused by a deficiency of the enzyme phenylalanine hydroxylase.

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