Question

What causes phenylketonuria?

Answer 1

Phenylketonuria:

1. Phenylketonuria is an autosomal recessive disease.
2. It is caused by the deficiency of the phenylalanine hydroxylase enzyme.
3. This enzyme converts phenylalanine to tyrosine.
4. When it is blocked, phenylalanine is converted to phenylpyruvate and excreted with the urine.
5. The signs of the disease are irritability, convulsions, mental retardation, microcephaly, and loss of pigmentation of skin, hair, and the iris.
6. Phenylketonuria is caused due to the lack of an enzyme that converts phenylalanine into tyrosine, i.e. phenylalanine hydroxylase.
7. It is an autosomal recessive trait.