Phenylketonuria

A rare inherited autosomal recessive condition with an estimated frequency of 1:10,000 new-born babies in the UK. It is caused by deficiency of liver enzyme phenylalanine hydroxylase (PAH) and its inability to convert phenylalanine from the diet, resulting in a build-up of phenylalanine in the body. These high levels of cause detrimental effect on brain development and function.