When do gut flora in the newborn produce 3-phenylpropionic acid? Implications for early diagnosis of medium-chain acyl-CoA dehydrogenase deficiency

M. J. Bennett, A. Bhala, S. F. Poirier, M. C. Ragni, S. M. Willi, D. E. Hale

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Urinary excretion of 3-phenylpropionylglycine (PPG) is a diagnostic marker for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. PPG is derived from 3-phenylpropionic acid (PPA), a product of anaerobic bacterial metabolism in the gut. To determine when the infant gut was colonized with PPA-producing bacteria, we cultured stool in prereduced thioglycollate broth from 93 apparently healthy infants. We analyzed the products of bacterial metabolism by gas chromatography/mass spectrometry for the presence of PPA. Trend analysis demonstrated a significant difference (P <0.001) in PPA production between early and later infancy. PPA was not detected in 84% of media isolated from stool collected from infants younger than four months. For older infants, 67% of the samples were PPA-positive. Thus, because the normal gut is not sufficiently colonized with PPA-producing bacteria before three to four months of age, PPG analysis alone is not a sensitive marker for the early detection of MCAD deficiency. Using stable isotope dilution mass spectrometry, we measured PPG and n-hexanoylglycine (HG) excretion in two well newborns with MCAD deficiency. HG, believed to be an endogenous metabolite associated with MCAD deficiency, was consistently above normal in all urine samples.

Original languageEnglish (US)
Pages (from-to)278-281
Number of pages4
JournalClinical Chemistry
Volume38
Issue number2
Publication statusPublished - Jan 1 1992

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Keywords

  • gas chromatography/mass spectrometry
  • heritable disorders
  • isotope dilution mass spectrometry
  • phenylpropionyl-glycine
  • urine

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, medical

Cite this

Bennett, M. J., Bhala, A., Poirier, S. F., Ragni, M. C., Willi, S. M., & Hale, D. E. (1992). When do gut flora in the newborn produce 3-phenylpropionic acid? Implications for early diagnosis of medium-chain acyl-CoA dehydrogenase deficiency. Clinical Chemistry, 38(2), 278-281.