Localized brain proton NMR spectroscopy in young adult phenylketonuria patients

Magn Reson Med. 1994 Jan;31(1):53-7. doi: 10.1002/mrm.1910310108.


Localized proton magnetic resonance spectroscopy with short echo time (TE = 20 ms) was used to investigate biochemical changes in the cerebral white matter of 20 young adult patients (median 19 years) with phenylketonuria (PKU). Results were compared with those of a group of 12 age-matched healthy volunteers (median 25 years). Concentrations of N-acetyl-aspartate (NAA) and choline (Cho) relative to creatine (Cr) were unchanged. However, concentrations of inositol (Ins) relative to creatine were found to be significantly lower (P < 0.001) in the PKU patients (0.30 +/- 0.09 versus 0.57 +/- 0.17). Individual inositol concentrations did not correlate with age, diet, serum phenylalanine (Phe) levels or extent of pathological regions in the T2-weighted images. The lack of correlation with individual data suggests that the decreased inositol concentration could be related to a metabolic deficiency during fetal development. No signal from the phenyl ring protons of phenylalanine was detected in the PKU patients (phenylalanine serum concentration < or = 1.27 mM), which suggests that concentration of phenylalanine may be lower in brain than in serum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aspartic Acid / analogs & derivatives
  • Aspartic Acid / analysis
  • Brain Chemistry*
  • Choline / analysis
  • Creatine / analysis
  • Female
  • Humans
  • Magnetic Resonance Spectroscopy*
  • Male
  • Middle Aged
  • Phenylketonurias / metabolism*


  • Aspartic Acid
  • N-acetylaspartate
  • Creatine
  • Choline