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Genetic and Rare Diseases Information Center (GARD)

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Other Names for this Disease
  • Fish malodor syndrome
  • Fish odor syndrome
  • Stale fish syndrome
  • TMAU
  • TMAuria
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Trimethylaminuria (TMAU) is a metabolic disorder in which an individual is not able to break down trimethylamine into smaller parts. Trimethylamine is the substance that gives fish their distinctive smell. Since an individual with TMAU is unable to break down trimethylamine, they tend to have a fish-like odor coming from their sweat, urine, reproductive fluids, and breath. TMAU is caused by a mutation in the FMO3 gene and is inherited in an autosomal recessive pattern. This condition can be diagnosed by a test to measure the amount of trimethylamine in urine. Genetic testing can also be performed using a blood sample to diagnose TMAU. Although there is no cure for TMAU, the condition can be managed by reducing the amount of trimethylamine in the body. For example, people with TMAU can modify their diet to avoid foods with high levels of trimethylamine.[1][2]
Last updated: 1/27/2014


  1. Trimethylaminuria. Genetics Home Reference Web site. January 2013; Accessed 1/27/2014.
  2. Phillips IR, Shephard EA. Trimethylaminuria. GeneReviews. April 19, 2011; Accessed 1/27/2014.
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Basic Information

  • Genetics Home Reference (GHR) contains information on Trimethylaminuria. This website is maintained by the National Library of Medicine.
  • The National Human Genome Research Institute's (NHGRI) mission encompasses a broad range of studies aimed at understanding the structure and function of the human genome and its role in health and disease. Click on the link to view the information page on this topic.
  • The National Organization for Rare Disorders (NORD) is a federation of more than 130 nonprofit voluntary health organizations serving people with rare disorders. Click on the link to view information on this topic.

In Depth Information

  • The Online Mendelian Inheritance in Man (OMIM) is an catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs.  Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Trimethylaminuria. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles