What condition results from poor metabolic processing of the amino acid phenylalanine?

Phenylketonuria (PKU) is a genetic disorder that arises from a deficiency in the enzyme phenylalanine hydroxylase, which is essential for the metabolism of the amino acid phenylalanine. When this enzyme is deficient or absent, phenylalanine accumulates in the body, leading to a range of harmful effects, particularly on brain development. If left untreated, PKU can cause intellectual disabilities, behavioral problems, and neurological issues.

In contrast, Huntington's Disease is a progressive neurological disorder caused by a genetic mutation unrelated to amino acid processing. Down Syndrome is a genetic condition caused by the presence of an extra chromosome 21, leading to developmental delays and physical features that are distinct from metabolic disorders. Cystic Fibrosis, on the other hand, is a genetic disorder affecting the lungs and digestive system, caused by mutations in the CFTR gene, and it does not involve abnormal metabolism of phenylalanine.

Understanding PKU and its implications is crucial, as early diagnosis through newborn screening can lead to dietary interventions that prevent the severe intellectual and developmental effects associated with the condition.