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Maternal non-phenylketonuric mild hyperphenylalaninemia

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Abstract

Unlike maternal phenylketonuria (PKU) which produces severe birth defects when untreated during pregancy, maternal non-PKU mild hyperphenylalaninemia (MHP) has a less severe impact but whether it is benign or may have long-term consequences for offspring has been unclear. From an international survey of maternal MHP we obtained information about 86 mothers (blood phenylalanine (Phe) 150–720 µmol/1), their 219 untreated pregnancies and 173 offspring. Spontaneous fetal loss and congenital anomalies were no more frequent than normally expected. Median Z-scores for birth length and birth head circumference and offspring IQ (100), however, were significantly lower for maternal Phe > 400 µjnol/1 than for maternal Phe <400 µmol/1, in which the median offspring IQ was 108. Data on maternal MHP from the prospective Maternal PKU Collaborative Study (MPKUCS) are as yet incomplete but seem to be conforming to the general pattern of the international survey. We conclude that maternal blood Phe levels above 400 µmol/1 in maternal MHP are associated with lower birth measurements and slightly lower offspring IQ. It would seem that dietary intervention to lower the maternal Phe levels to below 400 µmol/l might be indicated in maternal MHP pregnancies with the higher blood Phe levels.

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Abbreviations

Phe :

phenylalanine

PKU :

phenylketonuria

MHP :

non-PKU mild hyperphenylalaninemia

MPKUCS :

Maternal PKU Collaborative Study

GCI :

general cognitive index

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Authors and Affiliations

  1. I. C. Smith 106, Children’s Hospital, 300 Longwood Avenue, 02115, Boston, MA, USA

    H. L. Levy, S. E. Waisbren, D. Lobbregt, E. Allred & A. Leviton

  2. Medical School, Boston, MA, USA

    H. L. Levy, S. E. Waisbren & A. Leviton

  3. Children’s Hospital Los Angeles, Los Angeles, CA, USA

    R. Koch

  4. Hospital for Sick Children, Toronto, Ontario, Canada

    W. B. Hanley

  5. University of Texas at Galveston, Galveston, TX, USA

    B. Rouse

  6. Children’s Hospital, Miami, FL, USA

    R. Matalon

  7. National Institute of Child Health and Human Development NIH, Bethesda, MD, USA

    F. de la Cruz

Authors
  1. H. L. Levy
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  2. S. E. Waisbren
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  3. D. Lobbregt
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  4. E. Allred
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  5. A. Leviton
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  6. R. Koch
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  7. W. B. Hanley
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  8. B. Rouse
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  9. R. Matalon
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  10. F. de la Cruz
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Additional information

The conclusions in this article do not necessarily represent the conclusions of the Maternal PKU Collaborative Study.

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Levy, H.L., Waisbren, S.E., Lobbregt, D. et al. Maternal non-phenylketonuric mild hyperphenylalaninemia. Eur J Pediatr 155 (Suppl 1), S20–S25 (1996). https://doi.org/10.1007/PL00014243

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  • DOI: https://doi.org/10.1007/PL00014243

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