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Bony changes of PKU neonates unrelated to phenylalanine levels

R O Fisch1, S B Feinberg, S Weisberg

  • 1Department of Pediatrics, University Hospitals, Minneapolis, MN 55455.

Journal of Inherited Metabolic Disease
|January 1, 1991
PubMed

Insights

Bone abnormalities in infants with phenylketonuria (PKU) are common, affecting 77% of those studied. These mesodermal changes suggest an intrauterine amino acid imbalance rather than a postnatal dietary issue.

Area of Science:

  • Biochemistry
  • Pediatrics
  • Radiology

Background:

  • Bone abnormalities were first radiographically described in phenylketonuria (PKU) patients in 1962.
  • Neonatal observations allowed differentiation between inherited bone development alterations and dietary restriction effects.
  • Similar bone changes are noted in other aminoacidurias.

Purpose of the Study:

  • To investigate the prevalence of bone abnormalities in infants with phenylketonuria.
  • To determine the relationship between bone abnormalities, serum phenylalanine levels, and age at referral in PKU infants.

Main Methods:

  • Wrist radiographs and serum phenylalanine levels were collected from 73 PKU patients.
  • Radiographs were taken on the day of referral, with 49 patients under 28 days old.
  • A control group of 16 infants was used for comparison.

Main Results:

  • Bone abnormalities were present in 77% (56/73) of PKU infants, compared to 0% in the control group.
  • The presence of bone abnormalities was unrelated to serum phenylalanine levels.
  • Age at referral did not correlate with the presence or absence of bone abnormalities.

Conclusions:

  • The findings suggest that mesodermal changes in PKU infants are likely caused by an intrauterine amino acid imbalance.
  • This contrasts with the hypothesis that postnatal dietary deviations are the primary cause of these bone alterations.

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