The classical form of the metabolic disease phenylketonuria is caused by a mutation in the gene encoding the enzyme phenylalanine hydroxylase (PAH), which converts phenylalanine to tyrosine.A variant form of phenylketonuria is caused by a mutation in a separate gene that encodes a different enzyme involved in the synthesis of a cofactor needed for PAH to function.Which of the following phenomena is illustrated by these two forms of phenylketonuria?
A)Allelic heterogeneity
B)Compound heterozygosity
C)Locus heterogeneity
D)Anonymous polymorphism

Question

Quizplus · Accepted Answer

Locus heterogeneity refers to a situation where mutations in different genes can cause the same disease or phenotype. In the case of phenylketonuria, both the classical form (caused by mutations in the PAH gene) and the variant form (caused by mutations in a gene involved in cofactor synthesis for PAH) illustrate this phenomenon, as different genetic loci are involved in the same disease manifestation.

The Classical Form of the Metabolic Disease Phenylketonuria Is Caused