What condition is characterized by an accumulation of phenylalanine due to the body's inability to convert it to tyrosine?

The condition characterized by an accumulation of phenylalanine due to the body's inability to convert it to tyrosine is phenylketonuria (PKU). PKU is a genetic disorder resulting from a deficiency in the enzyme phenylalanine hydroxylase, which is needed to convert phenylalanine, an amino acid found in many protein-containing foods, into tyrosine. When phenylalanine builds up, it can lead to serious neurological issues and developmental delays if not managed through dietary restrictions.

Cystic Fibrosis, Muscular Dystrophy, Autism, and Hydrocephalus do not involve the metabolic processing of phenylalanine. Cystic Fibrosis primarily affects the respiratory and digestive systems due to thick mucus production, while Muscular Dystrophy refers to a group of genetic disorders affecting muscle strength and function. Autism is a developmental disorder impacting social interaction and communication, and Hydrocephalus involves the accumulation of cerebrospinal fluid in the brain. Each of these conditions has distinct causes and symptoms that are unrelated to the metabolic pathway of phenylalanine.