Adam.com: An Overview - A description of phenylketonuria, along with details of the causes, incidence and risk factors.
Children's PKU Network - Information about the organization and contact details as well as links to data about phenylketonuria.
Med Help: PKU - A description of phenylketonuria along with a look at the causes, incidence, symptoms and treatment.
National PKU News - Site includes news and information about phenylketonuria, a rare inherited metabolic disease.
NCBI: Genes and Diseases: Phenylketonuria - An article with full explanation as to what this disease is.