Studies on the discontinuous N-oxidation of trimethylamine among Jordanian, Ecuadorian and New Guinean populations

Pharmacogenetics. 1997 Feb;7(1):45-50. doi: 10.1097/00008571-199702000-00006.


Whilst the majority of individuals within a British white population are able to convert greater than 90% of their dietary-derived trimethylamine to its N-oxide, outliers exist who show varying degrees of impairment. Such individuals excrete unoxidized trimethylamine in their urine and, if sufficiently compromised, may experience malodour problems (Fish-Odour Syndrome). Little information concerning this polymorphic N-oxidation process is available in other ethnic groups and the present study explores Jordanian, Ecuadorian and New Guinean populations. Subjects with a relative deficiency in N-oxidation were found in all three groups, with 1.7% (2/116) Jordanian, 3.8% (3/8) Ecuadorian and 11.0% (11/100) New Guinean excreting 80% or less of their total trimethylamine as the N-oxide. Two subjects from the Ecuadorian population (4% and 33% total trimethylamine as the N-oxide) exhibited frank trimethylaminuria. These observations suggest that a compromised ability to N-oxidize trimethylamine is detectable in several ethnic groups and that this polymorphic phenomenon may have a widespread existence.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Confidence Intervals
  • Diet
  • Ecuador / ethnology
  • Ethnicity / genetics*
  • Female
  • Humans
  • Jordan
  • London
  • Male
  • Methylamines / pharmacokinetics*
  • Middle Aged
  • New Guinea / ethnology
  • Oxidation-Reduction
  • Pedigree
  • Polymorphism, Genetic*


  • Methylamines
  • trimethylamine