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Trimethylaminuria: The detection of carriers using a trimethylamine load test
Author(s) -
AlWaiz M.,
Ayesh R.,
Mitchell S. C.,
Idle J. R.,
Smith R. L.
Publication year - 1989
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1007/bf01805534
Subject(s) - trimethylamine , urine , urinary system , excretion , trimethylamine n oxide , chemistry , base excess , medicine , endocrinology , biochemistry
Summary A method potentially of value for investigating putative heterozygotes or carriers of trimethylaminuria by using a single oral dose of trimethylamine (TMA) is described. For healthy volunteers under normal dietary condition and following oral challenge with 300 mg and 600 mg TMA‐base, over 90% of the urinary TMA was excreted in the form of TMA (93.6 ± 1.6%). However, at a dose level of 900 mg TMA‐base, there was clear evidence of saturation of the N ‐oxidation reaction as urinary TMA excretion declined to 77.2% (range 74.8–78.9) of the total dose of TMA. By contrast, in pedigree studies based upon propositi with trimethylaminuria, several parents were identified who showed clear evidence of saturation of the N ‐oxidation of TMA at the 600 mg TMA‐base dose level, but not at 300 mg TMA‐base or under normal dietary condition. In these individuals, the proportion of urinary TMA as trimethylamine N ‐oxide (TMAO) declined to (77.3 ± 1.7%). Accordingly we propose that the oral administration of 600 mg TMA‐base and the analysis of the following 0–8‐h urine collection may be useful for the investigation of possible carriers of trimethylaminuria.