Phenylketonuria

PKU is an autosomal recessive disorder resulting from a deficiency of the hepatic enzyme phenylalanine hydroxylase (PAH), which converts phenylalanine to tyrosine (figure 1) (1). PAH deficiency is the most common cause of the accumulation of phenylalanine (Phe), called hyperphenylalanemia (HPA), with an incidence of roughly 1:10000 Caucasian live births, with a higher incidence in the populations of Turkey, Ireland and Norway (http://emedicine.medscape.com/article/947781-overview).