Trimethylaminuria (TMAU), also known as fish odour syndrome, is a metabolic disorder. TMAU usually presents with a body odour resembling that of rotten or decaying fish, the result of excess excretion of trimethylamine (TMA) in the breath, sweat, urine, and reproductive fluids. Primary TMAU is most often caused by a functional defect of flavin mono-oxygenase 3 (FMO3), and the genetic disorder is inherited in an autosomal recessive manner as a consequence of mutations in the FMO3 gene. Secondary TMAU has been described in patients with severe liver disease (which is the major site of activity of the FMO3 enzyme) and chronic renal disease (as a consequence of bacterial overgrowth in the gut), and in patients treated with large doses of betaine or possibly L-carnitine. In addition, transient TMAU has been reported in a preterm infant who was fed with choline-rich food supplements and has been reported in some women just at the onset of menstruation.
Inherited metabolic disease
Human diseases [BR:
Congenital disorders of metabolism
Other congenital disorders of metabolism
Human diseases in ICD-11 classification [BR:
05 Endocrine, nutritional or metabolic diseases
Inborn errors of metabolism
5C50 Inborn errors of amino acid or other organic acid metabolism
Drug metabolism - cytochrome P450
Trimethylaminuria: an under-recognised and socially debilitating metabolic disorder.
J Paediatr Child Health 48:E153-5 (2012)
Shephard EA, Treacy EP, Phillips IR
Clinical utility gene card for: trimethylaminuria.
Eur J Hum Genet 20:ejhg2011214 (2012)
Fraser-Andrews EA, Manning NJ, Ashton GH, Eldridge P, McGrath J, Menage Hdu P
Fish odour syndrome with features of both primary and secondary trimethylaminuria.
Clin Exp Dermatol 28:203-5 (2003)
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