Reference work entry

Trimethylaminuria, also called fish odor syndrome, is a metabolic disorder characterized by a distinctive decaying fish odor of sweat, urine, breath, and other body secretions due to presence of abnormal amounts of the dietary-derived tertiary amine, trimethylamine (TMA).

Synonyms and Related Disorders

Fish-odor syndrome

Genetics/Basic Defects

  1. 1.
    Inheritance (Rehman 1999)
    1. a.

      Autosomal recessive

    2. b.

      The incidence of heterozygous carriers of the allele for impaired N-oxidation is estimated to be of the order of 1%.

  2. 2.
    Basic defect
    1. a.

      Caused by deficiency of the flavin-containing mono-oxygenase isoform 3 (FMO3). A defect in hepatic N-oxidation of dietary-derived TMA causes excess excretion of TMA, leading to affected individuals to have a body odor resembling rotten fish (Basarab 1999).

    2. b.

      Caused by loss-of-function mutations in the FMO3gene (mapped on 1q24.3) encoding an isoform of flavin-containing mono-oxygenase have been shown to underlie trimethylaminuria/fish odor syndrome...


Temporal Lobe Epilepsy Bacterial Vaginosis Preimplantation Genetic Diagnosis Proton Nuclear Magnetic Resonance Body Odor 
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