HBRI currently receives no funding for its TMAU program other than through donations. The program is quite expensive to maintain but we beleive that this important research should be continued.

If you would like to help support this important program, please visit our giving page or click here to donate now.

HBRI is a 501(c)3 non-profit.











The Trimethylaminuria Foundation (not affiliated with HBRI) is a good source of information on TMAU. They can be contacted by at TRIMETH411@aol.com or by calling 212-300-4168.


Due to lack of program support and funding, HBRI is no longer accepting samples for TMAU testing..

TMAU testing is currently available at the Monell Chemical Senses Center (not affiliated with HBRI).

*If you think you, or someone you know, may have TMAU, please read this page.

What is TMAU?

Trimethylaminuria (TMAU) is a genetically-mediated disorder, which appears to be inherited in an autosomal, recessive fashion. This was discovered initially by studying sufferers and their families, and more recently, by examining the molecular deficits responsible for TMAU. The biochemical deficit causing TMAU is the inability to completely metabolize trimethylamine (TMA) to TMA-oxide (TMAO) in the liver. TMAO is a non-volatile (non-odorous) solid that is excreted in urine. The enzymes catalyzing this conversion are the microsomal, flavin-containing monooxygenase (FMO). The FMO family of enzymes are catalytically diverse and catalyze the oxygenation of a variety of heteroatom-containing (N-, S-, P-) endogenous and xenobiotic compounds.

The principle presenting symptoms of TMAU stem from excess, unmetabolized trimethylamine. TMA is formed in the gut by bacterial metabolism of dietary constituents, principally choline. TMA is a gas at body temperature and has a foul, fishy odor. At very low concentration, it may only be perceived as foul, unpleasant or “garbage-like”. Excessive production of TMA is linked to the intake of a variety of choline rich foods, (such as eggs, certain legumes, fish and organ-meats) hence the sporadic production of symptoms. Because there are many foods that are rich in choline, both patients and their family members are unlikely to relate the odor to food intake.

Symptoms may include foul body odors, halitosis and/or dysguesia, which can produce social embarrassment and can be temporarily relieved by normal hygiene procedures. Further, the unpleasant symptoms are often sporadic in occurrence and seemingly subjective, and when coupled with a lack of knowledge of the disease and its etiology among health professionals, may lead to diagnosis of poor hygiene, psychiatric problems, and/or referrals to other specialists. The latter has been financially draining many patients.

Several reports in the literature have described other complications occurring in conjunction with TMAU, such as seizures, skin rashes and syndromes (Prader-Willi, and Noonan’s). However, the vast majority of patients appear to have normal mental and physical abilities, lead normal lives and have good hygiene practices. The main problem afflicting most patients are psycho-social ones cause by sporadic, unexplained odor production.

More Information on TMAU.
(HBRI does not sponsor or endorse the following websites.)

Visit the National Institutes of Health, Office of Rare Diseases' website for more information and links regarding TMAU.

Visit the GeneReviews, developed by the University of Washington, Seattle, for more information and resources on Trimethylaminuria.

Visit the USDA's website for USDA's Database for the Choline Content
of Common Foods

Click here to read the abstract from a recent article on TMAU co-authored by HBRI's Director, Dr. Cashman.

The Trimethylaminuria Foundation (not affiliated with HBRI) is a good source of information on dealing with TMAU after a positive diagnosis. They can be contacted by email at TRIMETH411@aol.com or by calling (212) 300-4168.