Phenylketonuria (fee-null-keet-o-noo-ria), mercifully also known as “PKU” (pee – kay – you) is a disorder in which phenylalanine, an essential amino acid, is not broken down as it normally would be by an enzyme (phenylalanine hydroxylase) and thus accumulates (in the form of phenylpyruvic acid) in the body. Normally, Phenylalanine hydroxylase coverts phenylalanine into tyrosine, another amino acid, which has a number of different functions.

This is bad because buildup of phenylpyruvic acid has several negative effects, the most important being to interfere with normal development of neural tissues. Continue reading PKU: An exploration of a metabolic disease →