title: Diagnosis of suspected trimethylaminuria by NMR spectroscopy.
abstract: BACKGROUND
  Trimethylamine (TMA) is a volatile substance produced in the gut, absorbed into the blood and further metabolized by healthy individuals into trimethylamine-N-oxide (TMAO) by TMA-oxidase and then excreted in urine. Patients suffering from trimethylaminuria (TMAU) show an impaired enzymatic oxidation of TMA, excreting this amine in breath, urine and other body secretions which confers an unpleasant body odor.
  
  
  METHODS
  We diagnosed a Brazilian adult male patient suspected of trimethylaminuria with a burden of choline bitartarate by monitoring the urinary excretion of TMA and TMAO by proton nuclear magnetic resonance spectroscopy ((1)H-NMR).
  
  
  RESULTS
  The patient's urinalyses showed an augmented TMA (12.64+/-0.95 mg/l) and TMAO (88.42+/-0.82 mg/l) excretion 6 h after the overload test representing an oxidation capacity of 84.6%, consistent with a heterozygosis condition. Diets containing tuna fish or eggs resulted in an excretion of TMA and TMAO similar to that of the control diet. Only the diet based on dogfish, rich in TMAO, enhanced the excretion of TMA and TMAO reaching 24.65 and 1055.55 mg/l, respectively, in the 0-24 h urine sample.
  
  
  CONCLUSIONS
  It was concluded first, that the patient was not able to metabolize the dietary overload of TMA and second, that more studies are needed to substantiate foods that should be avoided, especially regarding fish, due to their high TMA precursor contents.
authors.affiliation: Departamento de Alimentos e Nutrição Experimental, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 580, CEP 05508-900-São Paulo, Brazil.
authors.forename: Priscilla
authors.initials: P
authors.lastname: Podadera
authors.forename: Aytan M
authors.initials: AM
authors.lastname: Sipahi
authors.forename: Jose A G
authors.initials: JA
authors.lastname: Arêas
authors.forename: Ursula M
authors.initials: UM
authors.lastname: Lanfer-Marquez
mesh_terms: D000328:Adult; D000588:Amines / Q000378:metabolism / Q000652:urine; D000818:Animals; D002794:Choline / Q000493:pharmacokinetics; D004032:Diet; D004284:Dogfish; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008661:Metabolism, Inborn Errors / Q000652:urine*; D008744:Methylamines / Q000652:urine*; D009812:Odorants; D010084:Oxidation-Reduction; D012015:Reference Standards; D012996:Solutions
chemical_list: D000588:Amines; D008744:Methylamines; D012996:Solutions; C005855:trimethyloxamine; C023336:trimethylamine; D002794:Choline