Management of phenylketonuria for optimal outcome: a review of guidelines for phenylketonuria management and a report of surveys of parents, patients, and clinic directors.

Objective: The development of guidelines for phenylketonuria (PKU) management in the United Kingdom has resulted in much discussion in the community of parents and PKU clinics and parents have asked why the United States does not have such guidelines. The objective of this report is to discuss PKU management in the United States, the British guidelines on PKU management, and the feasibility, suitability, and mechanism of developing PKU management guidelines in the United States.

Methods: Members of the American Academy of Pediatrics (AAP) Committee on Genetics (COG) reviewed the literature and conducted surveys of parents of children with PKU, young adults with PKU, and directors of PKU clinics in the United States.

Physical growth of children treated for phenylketonuria.

The growth of 133 children participating in the Collaborative Study of Children Treated for Phenylketonuria (PKU) was compared to growth data from the National Center for Health Statistics (NCHS) to determine whether the growth patterns of the children with PKU were the same as those of unaffected children. Height and weight by age, and weight by height, were analysed for ages 2-10 years. Head circumference by age was analysed for ages 2-7 years.

Reinstitution of diet therapy in PKU patients from twenty-two US clinics.

In a nationwide survey we found 72 PKU (phenylketonuria) patients who had terminated diet but later returned to diet. Sixty-one patients resumed diet due to clinical problems. Age at initial diet discontinuation ranged from three to 20 years.

Biopterin synthesis defects: problems in diagnosis.

Hyperphenylalaninemia due to a biopterin synthesis defect was detected in an infant with decreased biopterin and increased neopterin levels in plasma and urine. Tetrahydrobiopterin (BH4) administration normalized plasma phenylalanine levels. CSF biopterin and neurotransmitter metabolite levels were normal and with the infant's normal growth and development suggest that the defect in biopterin synthesis did not affect CNS biopterin metabolism.

Diet policies of PKU clinics in the United States.

About two-thirds of 90 clinics treating phenylketonuria (PKU) now recommend indefinite continuation of a low phenylalanine diet as compared to 1978 when fewer than one-fourth had this policy. The percentage of children maintained on diet has increased markedly for six to eight year-olds. Greater conservatism in clinic diet recommendations likely reflects reports of adverse consequences following diet discontinuation and negative individual clinic experiences.

EEG in phenylketonuria. Attempt to establish clinical importance of EEG changes.

To determine the importance of an abnormal EEG in phenylketonuria (PKU), we reviewed 137 EEGs from 48 patients with PKU. Patients were divided into three groups: group 1 (n = 14) had only normal EEGs, group 2 (n = 20) had only abnormal EEGs, and group 3 (n = 14) initially had normal EEGs that later became abnormal. The most common EEG abnormality was focal paroxysmal discharge.

Diet discontinuation policies and practices of PKU clinics in the United States.

Marked diversity in policies and practices for discontinuation of the PKU diet in the U.S. was found in a nationwide survey.