Given below are two statements :

Statement I : Phenylketonuria is an example of pleiotropy .

Statement II : Affected individual lacks an enzyme that converts phenylalanine into tyrosine.

In the light of the above statements, choose the most appropriate answer from the options given below :

Both statement I and statement II are correct .

The correct answer is Option (1) - Both statement I and statement II are correct .

Phenylketonuria : This inborn error of metabolism is also 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.One of the most widely cited examples of pleiotropy in humans is phenylketonuria (PKU). This disorder is caused by a deficiency of the enzyme phenylalanine hydroxylase, which is necessary to convert the essential amino acid phenylalanine to tyrosine.