Model of inital management of phenylketonuria and other hyperphenylalaninemias at the Instituto Nacional de Pediatria

Hyperphenylalaninemias are a group of autosomal recessive diseases produced in 98% of the cases by impaired activity of phenylalanine hydroxilase (PAH). The phenotype ranges from classic phenylketonuria (OMIM 261600, CIE-10 E090) to mild hyperphenylalaninemia. A high blood level of phenylalanine produces chronic encephalopathy in children, characterized by vomit, refusal to eat, irritability, skin and hair hypopigmentation, eczema, myoclonus, seizures and delay in developmental milestones whose final consequence is usually severe and irreversible mental retardation. For almost 50 years it has been known that early treatment of these conditions attenuates brain damage and can prevent intellectual and motor disabilities. Hyperphenylalaninemia is the most common aminoacid metabolic disorder diagnosed at the Instituto Nacional de Pediatria (INP). This Institute has a long and well documented experience in this disease; it is a referral centre with a multidisciplinary team, advanced technology for the diagnosis and follow-up of patients. The objective of this paper is to show the workshop algorithms for patients suspected of hyperphenylalaninemia seen at the INP, from their first visit at the outpatient clinic to the final diagnosis, in order to provide timely management.