Given below are two statements.
Statement I: Phenylketonuria is an example of pleiotropy.
Statement II: Phenylketonuria is associated with mental retardation, lighter skin, hair and eye colour.
In light of the above statements, choose the correct answer from the options given below.

An example of pleiotropy is the disease phenylketonuria, which occurs in humans. The disease is caused by a mutation in the gene that codes for the enzyme phenyl alanine hydroxylase (single gene mutation). This manifests itself through phenotypic expression characterised by mental retardation and a reduction in hair and skin pigmentation.