Statement I: Phenylketonuria is an inborn error of metabolism and is inherited as the autosomal recessive trait. In this the person is mentally retarded.
Statement II: In Phenylketonuria the individual lacks an enzyme that converts amino acid phenylalanine into tyrosine as a result of which phenylalanine is accumulated and converted into phenylpyruvic acid and other derivatives.

Both statements I and II are correct.

The correct answer is Option (3)-Both statements I and II are correct.

Phenylketonuria : This inborn error of metabolism is inherited as the autosomal recessive trait. The affected individual lacks an enzyme that converts the amino acid phenylalanine into tyrosine. As a result of this phenylalanine is accumulated and converted into phenylpyruvic acid and other derivatives. Accumulation of these in brain results in mental retardation. These are also excreted through urine because of its poor absorption by kidney.