What condition is associated with a deficiency in a key enzyme leading to potential brain damage?

What condition is associated with a deficiency in a key enzyme leading to potential brain damage?

• A. Cystic fibrosis
• B. Phenylketonuria (PKU)
• C. Down syndrome
• D. Autism spectrum disorder

Answer: (B)

Phenylketonuria (PKU) is associated with a deficiency in the enzyme phenylalanine hydroxylase. This enzyme is crucial for the metabolism of the amino acid phenylalanine, which is found in many protein-containing foods. When this enzyme is deficient or absent, phenylalanine can accumulate to toxic levels in the body, leading to serious neurological damage and cognitive impairment if not managed properly. Individuals with PKU require a strict diet low in phenylalanine to prevent the harmful effects of this accumulation. Early diagnosis through newborn screening has significantly improved outcomes, as timely dietary intervention can prevent intellectual disability and developmental delays associated with untreated PKU. In contrast, the other listed conditions are not primarily linked to an enzyme deficiency that leads to brain damage. Cystic fibrosis is a genetic disorder affecting the lungs and digestive system, Down syndrome is a genetic condition resulting from an extra chromosome 21, and autism spectrum disorder encompasses a range of neurodevelopmental conditions that are not caused by specific enzyme deficiencies.

Phenylketonuria (PKU) is associated with a deficiency in the enzyme phenylalanine hydroxylase. This enzyme is crucial for the metabolism of the amino acid phenylalanine, which is found in many protein-containing foods. When this enzyme is deficient or absent, phenylalanine can accumulate to toxic levels in the body, leading to serious neurological damage and cognitive impairment if not managed properly.

Individuals with PKU require a strict diet low in phenylalanine to prevent the harmful effects of this accumulation. Early diagnosis through newborn screening has significantly improved outcomes, as timely dietary intervention can prevent intellectual disability and developmental delays associated with untreated PKU.

In contrast, the other listed conditions are not primarily linked to an enzyme deficiency that leads to brain damage. Cystic fibrosis is a genetic disorder affecting the lungs and digestive system, Down syndrome is a genetic condition resulting from an extra chromosome 21, and autism spectrum disorder encompasses a range of neurodevelopmental conditions that are not caused by specific enzyme deficiencies.