Genetic and Rare Diseases Information Center (GARD)


Other names people use for this condition
  • TMAU
  • Fish odor syndrome
  • Fish malodor syndrome
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Trimethylaminuria
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Can the high levels of trimethylamine and fishy smell just involve the urine?



  • What is trimethylaminuria? (Back to Top)

  • Trimethylaminuria is a metabolic disorder in which an individual is not able to break down trimethylamine into smaller compounds. Trimethylamine is the compound that gives fish their fishy odor. Trimethylaminuria, has been around for centuries, but has only gained scientific recognition and support in the past 30 years.[1]
  • Last Reviewed: 2/11/2009

  • What causes trimethylaminuria? (Back to Top)

  • People with trimethylaminuria lack the enzyme flavin-containing monooxygenase 3 (FMO3), which is produced by the liver and is part of a family of similar enzymes responsible for breaking down compounds that contain nitrogen, sulfur, or phosphorous.[3] This enzyme is produced by the FMO3 gene. Not all of the functions of the FMO3 enzyme are known, so physicians don't know what other symptoms besides odor may be associated with trimethylaminuria.[1][2]
  • Last Reviewed: 2/11/2009

  • Can the high levels of trimethylamine and fishy smell just involve the urine? (Back to Top)

  • Patients with trimethylaminuria release the accumulated trimethylamine through body secretions which include, but is not limited to, the urine.[1] The trimethylamine is also released in the person's sweat, reproductive fluids, and breath, giving off a fishy odor.[1] However, symptoms and symptom severity may vary in people with trimethylaminuria. If you or someone you know is concerned that they may have trimethylaminuria, we recommend speaking with a healthcare provider.
  • Last Reviewed: 2/11/2009

  • Is testing available for trimethylaminuria? (Back to Top)

  • Yes. Diagnostic testing for trimethylaminuria is conducted by a urine test that measures the percentage of total trimethylamine that is excreted.[2] Urine testing should be performed on two separate occasions when the individual is on a non-restricted diet.[2] In addition to urine testing, carrier testing is also available for trimethylaminuria. This test is called either a 'TMA challenge' or a 'TMA load' test. It involves giving an individual a 600mg capsule of trimethylamine. Carriers of trimethylaminuria excrete 20-30% of total trimethylamine as the free unmetabolized amine, while non-carriers excrete less than 13%.[2]

    The laboratories listed below provide clinical diagnostic testing for elevated levels of trimethylamine in the urine. The Information Center provides the names of these centers for informational purposes only, not as an endorsement of the institutions' products or services. Please note that some laboratories do not accept direct contact from patients. Therefore, we recommend that you work with a medical or genetics professional to contact these laboratories for further information.

    Univeristy of Colorodo Health Sciences Center
    Contact: Dr. Susan Tjoa
    Phone: 303-315-8175
    E-mail: susan.tjoa@uchsc.edu

    The Human Biomolecular Research Institute
    5310 Eastgate Mall
    San Diego, CA 92121
    Phone: 858-458-9305
    Fax: 858-458-9311
    Email: rhandley@hbri.org
    Web site: http://www.hbri.org/

    Monell Chemical Senses Center
    University of Pennsylvania
    Phone: 267-519-4700
    Contact: George Preti, PhD 
    E-mail: preti@monell.org  
    Web site: http://www.monell.org/tmau_h.htm
    For more information, patients can send an e-mail to: bodyodorinfo@monell.org.

    In addition to urine testing, gene sequencing to look for mutations in the FMO3 gene is available.[2]  Click here to view the contact information for laboratories conducting genetic testing for trimethylaminuria.  Once again, please note that most laboratories do not accept direct contact from patients and their families; therefore, you will need to work with a health care provider if you are interested in learning more. 
  • Last Reviewed: 3/27/2009

  • What are the symptoms of trimethylaminuria? (Back to Top)

  • Trimethylamine accumulates in the body of patients with trimethylaminuria. The trimethylamine gets released in the person's sweat, urine, reproductive fluids, and breath, giving off a strong fishy odor. Some people with trimethylaminuria have a strong odor all the time, but most have a moderate smell that varies in intensity over time. Individuals with this condition do not have any physical symptoms, and typically appear healthy.[2]
  • Last Reviewed: 2/11/2009


References  (Back)
  1. Learning about Trimethylaminuria. National Human Genome Research Institute Web site. February 3, 2009 Available at: http://www.genome.gov/11508983 . Accessed February 11, 2009.
  2. Trimethylaminuria. Genetics Home Reference Web site. April 2007 Available at: http://ghr.nlm.nih.gov/condition=trimethylaminuria. Accessed February 11, 2009.
  3. Phillips IR, Shephard EA. Trimethylaminuria. GeneReviews Web site. March 18, 2008 Available at: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=trimethylaminuria. Accessed February 11, 2009.
        • Genetics Home Reference (GHR) contains a condition summary on Trimethylaminuria. Click on the link to go to GHR and review this summary.
        • The Online Mendelian Inheritance in Man (OMIM) database contains genetics resources that discuss Trimethylaminuria. Click on the link to go to OMIM and review these resources.
        • 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.
        • GeneReviews provides a comprehensive review describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions. Click on GeneReviews to view the article on Trimethylaminuria.
        • The United States Department of Agriculture has a document that lists the choline content of common foods. Click on the link above to view this document.
        • Trimethylaminuria Foundation
          P.O. Box 3361
          Grand Central Station
          New York, NY 10163-3361
          Telephone: 212-300-4168
          Fax or alternate phone: 917-640-7308
          E-mail: theTFnetwk@aol.com
          Hours of operation: Tu, Th, Fr until 7 pm and Saturdays until 4 pm
        • Trimethylaminuria Midwest Region Foundation
          12537 Hardy Street
          Overland Park, Kansas 66213
          Contact: Cheryl Fields, MBA
          Telephone: 913-906-9496
          Email: emporia962000@yahoo.com
        • The National Organization of Rare Disorders (NORD) has partnered with Inspire.com to launch an online community for people with rare diseases called The NORD Rare Disease Community. This community connects medical patients, family members, caregivers, and professionals. Click on The NORD Rare Disease Community to learn more.
        • RareShare is an online social hub dedicated to patients, families and healthcare professionals affected by rare medical disorders. Click on RareShare to learn more.
      • There is a study, entitled "Studies of Children with Metabolic and Other Genetic Diseases,'' which is evaluating individuals with known or suspected genetic or metabolic diseases. Despite its title, this study is enrolling individuals of all ages. Since this is a very broad study, individuals with this condition may be eligible to participate. To read about this study online, visit the link above. After you click on the study, review its 'eligibility' criteria to determine its appropriateness.
        • The GeneTests web site lists laboratories performing clinical diagnostic testing. The laboratory testing for TMAU is located in Canada, however, they accept samples from people in the United States. To find out more about this laboratory, click here or select the 'Laboratory Directory' icon at the top the home page. Use 'trimethylaminuria' as your disease search term and click on either the 'Research' or 'Testing' icon for the laboratory's contact information. Again, please note that this laboratory does not accept direct contact from patients; therefore, you will have to work in conjunction with a health care provider or genetics professional. Either of these professionals can contact the laboratory to learn more about the clinical diagnostic testing the laboratory offers for trimethylaminuria.
        • The Human Biomolecular Research Institute can assist in the diagnostic testing of patients who may have trimethylaminuria.


          The Human Biomolecular Research Institute
          5310 Eastgate Mall
          San Diego, CA 92121
          Tel: (858) 458-9305
          Fax: (858) 458-9311
          Email: rhandley@hbri.org
          Web site: http://www.hbri.org/
        • The Monell Chemical Senses Center is able to assist in the diagnostic testing of patients who may have trimethylaminuria. Monell is a non-profit, basic scientific research center focused on understanding the senses of taste and smell. They are not a medical clinic. If you are interested in more information, you can send an e-mail to bodyodorinfo@monell.org. The Information Center provides the names of these centers for informational purposes only, not as an endorsement of the institutions' products or services.


          Monell Chemical Senses Center
          University of Pennsylvania
          Telephone: (267) 519-4700
          Contact: George Preti, PhD at preti@monell.org
          Web site: http://www.monell.org/tmau_h.htm
        • University of Colorado Health Science Center is able to assist in the diagnostic testing of patients who may have trimethylaminuria. Please note that some laboratories do not accept direct contact from patients. Therefore, we recommend that you work with a medical or genetics professional to contact the laboratories for further information. The Information Center provides the names of these centers for informational purposes only, not as an endorsement of the institutions' products or services.


          Dr. Paul Fennessey (303) 315-7287
          Contact: Dr. Susan Tjoa; (303) 315-8175 or susan.tjoa@uchsc.edu

        • We recommend that you discuss this information and your concerns with a genetics professional. The following online resources can help you find a genetics professional in your community:

           * GeneClinics - A searchable directory of US and international genetics and prenatal diagnosis clinics. To locate genetics clinics in the United States, go to the following link and click on 'Clinic Directory' to find a genetic service close to you. 

            * ResourceLink - A database of genetics counseling services, searchable by location, name, institution, type of practice, or specialty. Hosted by the National Society of Genetic Counselors.

      • The NLM Gateway allows users to search across multiple resources offered on the National Library of Medicine's Web site.  Some of these resources may be duplicated in the list of links above.  Click on the link to go to the NLM Gateway, and search by condition name.

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