Synonymous with rare diseases are mental health issues, loneliness, and lack of hope. As healthcare is still a business, money rules all decisions. There is no pure or greater good motivation behind the largest medical institutions. Where this is seen, particularly, is within the rare disease communities our team has researched. While it is impractical to try to find a solution to all the rare diseases that we came across, our team decided to pick a disease that had been ignored by the medical community. Trimethylaminuria is at the heart of rare diseases, nearly abandoned by the healthcare system. There is very little research is being done despite the lack of treatments. Due to the lack of "serious" health risks, the medical community has ceased to look further into this disease, causing those suffering from it to suffer in isolation, with no hope of it getting better.

What is Trimethylaminuria?

Trimethylamine, or TMA, is the metabolite associated with the rotting fish odor. TMA is a gut microbiota-dependent metabolite formed in the small intestinal lumen. TMA is formed when gut microbiota metabolizes carnitine, choline, and choline-containing compounds in the diet. The build up of TMA in the blood stream is what causes the rotting fish smell to pour off of these patients suffering from TMAU. The smell can be released out of the body through sweat, tears, saliva, etc.

As seen in the Figure when two carriers of the dysfunctional FMO3 gene have a child, there is a 25% chance that the child will inherit two copies of the defective gene and develop TMAU, a 50% chance that the child will inherit one defective gene and be a carrier like the parents, and a 25% chance that the child will inherit two normal copies of the gene and not have TMAU.

Figure: Autosomal Recessive Pedigree of Trimethylaminuria (TMAU)

Psychological and Societal Effects of TMAU

Smell is a nonphysical feature that humans try to enhance, as good hygiene is important to future/current employers, partners, friends, etc. The problem with smell, especifically foul smells, is it is very hard to mask. Soaps, deodorants, and colognes are made to remove and/or replace poor smells with vibrant citrusy and oaky scents. However, they weren’t made to mask the rotten fish smell that seeps out of every pore of patients suffering from TMAU. Due to this weakness, these patients find no relief in any soap or cologne, no matter how expensive or all-natural. According to various TMAU patients, "Bathing multiple times a day and using a higher pH soap has done nothing to mask my smell." The smell coming off of their bodies is not only unpleasant, but it also very detectable by the human nose. As the nose can smell TMA in concentrations as low as less than 0.12 parts per billion [3], these people are outcasts from society as no one wants to be around or be close to someone that smells like rotting fish. Multiple patients that our team spoke with claimed "I've had people spray perfume in my direction and make disgusted faces just being within ten feet of me". Isolation is something humans do not mentally thrive in, as those suffering from this disease are isolated from their friends and families. Most TMAU patients explained they stopped hanging out with friends and family in public, if at all. One patient told our team, "How can I go and spend time with friends if I am constantly worrying about my uncontrollable smell. And it makes it even harder when I can't go on public transportation without drawing in the attention of everybody around me". This isolation causes a variety of mental health issues, primarily depression.

stakeholder map

Establishing a Network

Finding medical professionals who are still working with TMAU, or have a decent knowledge of the disease, was a lot more difficult than our team expected. Digging through a plethora of medical websites that might have mentioned the disease once and didn’t list anyone further to contact, we understood the most difficult task for these patients is finding someone who understands what they have. After hours of multiple team members digging through the internet trying to find someone who can help, we discovered Dr. Timothy Wood.

As stated previously, after months of research and reaching out to various stakeholders so our team had a solid base of knowledge, our team found a TMAU testing center in the Colorado Children’s Hospital in Aurora, Colorado. Our team then decided to meet with Dr. Timothy Wood. Dr. Wood is the lab director at the Colorado Children’s Hospital where he works on the diagnosis of metabolic diseases and specializes in clinical biochemical genetics, clinical genetics, and genomics.

Our team asked many important questions to Dr. Wood to which he provided much needed answers. Through our meeting, we learned that the testing center in Colorado used urine-based testing to test for TMA. We learned that TMAO levels should be 90% or greater, if not, there is a high possibility of the patient containing an overabundance of TMA and, therefore, suffering from TMAU. Dr. Wood also explained that certain lab-developed test kits are available, however, many medical providers refuse to order them for patients as many believe these patients are just mentally ill or have poor hygiene.

Another major takeaway was that a discrepancy was noticed in genetic testing between TMAU patients. Some TMAU patients would have certain genetic mutations or dysfunction that would label them as TMAU patients. However, some people would not have those gene mutations and still release a body odor similar to those with TMAU. This causes even more turmoil in the medical world that already does not have much knowledge on TMAU. This caused medical professionals to deny testing people claiming to have TMAU, and instead, recommending them to psychiatrists diagnosing them with neurological disorders. These stories by Dr. Wood and his experiences with TMAU emphasizes the lack of knowledge and missing information behind this disease that inflicts immense suffering to those affected.

The last takeaway that truly makes this disease devastating is while testing is available, it is very expensive. Patients have told us their tests have costed over $600. Some people may argue that this is not overly expensive, however, being as most dealing with this disease have less than ideal incomes due to the work isolation, many cannot afford to get tested. Going one step further, even if people were able to save up the money to get tested, there is no next step for them; there are no treatments. Therefore, many individuals who believe they would test positive for this disease decide not to get tested consequently decreasing the known effected population and decreasing the interest of the medical world.

stakeholder map

This Stakeholder Map labels each different stakeholder and the corresponding impact on the project.

Initial Therapeutic Thoughts

After our meeting with Dr. Wood, our team had many great takeaways, and our design team derived a few possible solution ideas, including microbiome transplant and enzyme pill. Through the weeks of the design team brainstorming what would be the most practical and effective method of treatment we could provide to these patients, the team ranked various solutions. Based on feasibility, patients experience, and innovation, through a team vote, it was decided that creating a enzymatic pill, similar to a lactase pill, was the best route to take for the team. While no small task, the team believed that the enzymatic pill is not only achievable to do with in the summer and fall months, but it would be the most effective form of treatment.

Dr. Ariel Lindner is a research director at the French National Institute of Health and Medical Research (INSERM). Dr. Lindner was also a member of the 2014 Paris Bettencourt IGEM team. This IGEM team also worked with TMA and Trimethylaminuria, therefore, our team thought it would be extremely beneficial to meet with Dr. Lindner.

Our discussion with Dr. Lindner proved to be very helpful as we discussed how the trimethylamine monooxygenase (TMM) enzyme would be the most useful enzyme to use in our project. Dr. Lindner explained how his 2014 team used this enzyme and how their team proposed to use this modified TMM enzyme on the surface of the skin to treat the TMAU odor. He also provided our team with various ways to connect to the TMAU community, for example, the MEBO Research group, Rare connect, and many more social media platforms.

After extensive work from our design team, our team was counseled by one of our advisors, Michael Taylor, to seek a meeting with Dr. Jake Wintermute. Dr. Wintermute is a synthetic biologist and evangelist who works at Ginkgo Bioworks. Dr. Wintermute was also a member of the 2014 Paris Bettencourt IGEM team who also targeted trimethylaminuria.

Design Complications

The main point of discussion our team had with Dr. Wintermute was the topic of oxygen availability of the small intestine, as this is where TMA and/or TMAO is absorbed through the lining into the blood stream. As many enzymes require oxygen to perform a task, it became apparent that it is necessary to either pick an enzyme that does not require oxygen or, in the pill, supply the oxygen needed to convert TMA into TMAO.

What our team learned later through a meeting with Dr. John Oliver, Vice President of Research and Development at ZBiotics, is that oxygen concentration is great enough along the lining of the small intestine for oxygen requiring enzymes to function properly. This lessened the need for our team to find an enzyme doesn't need oxygen, however, our team still considered anaerobic enzymes for the probiotic pill.

Returning back to the conversation our team had with Dr. Wood, before concluding the interview, our team made sure to ask who we should speak to next. Dr. Wood recommended Jillian Kirk, who in March 2023, was a master's student under Dr. Wood, whose thesis was on TMAU patient experience. Our team reached out to Jillian and were able to schedule an interview later that month to ask about the community feedback she got from her research. With extensive work in public outreach to this community, Kirk was only able to get less than 100 responses from people who suspect they have TMAU. From that 100, less than 20 of them were actually tested via a urine sample and proven to have TMAU. These survey numbers/responses show how rare this disease is and how hard it is to tap into this community. Jillian Kirk is a certified genetic counselor at AdventHealth.

Inconvenience of Testing

The lack of testing is a large fallout in the community due to the price and inconvenience of testing sites. While someone may present with similar symptoms as someone with TMAU, it is not guaranteed that they are suffering from it, as there are many other rare diseases that have caused people to reek of unpleasant odors. The most prominent message we gained from our meeting with Jillian Kirk was these patients want relief. Relief could be created in many different ways; whether it be a soap that works for half the day, allowing someone to be smell free as long as they go home to shower on their lunch break, or whether it be an enzyme pill that removes half of the TMA build up. Relief is what these patients are desperate for, as no one has advocated or seen for the unimaginable damage this disease has done. Advocating for these patients, if nothing else, was a priority for our team. The more physicians and researchers hear about this disease, the better chance patients have at getting the proper medical care and diagnosis.

Face to Face

Karen was the first TMAU patient that our team met with through Zoom. Karen had reached out to us through RareConnect and provided her contact information and stated she would love to speak with us and tell us about her experience with TMAU. Karen explained to us that her symptoms began in December 2004 when she was 18 years old. At first, she explained she did not notice a bad smell and was not until she noticed people around her reacting to her presence in a negative way. It then got much worse with people making faces and rude comments while on public transportation and even at work people would make fun of her and tell her to shower and spray perfumes at her. She did not understand why she was smelling bad, even after taking multiple showers her smell would not go away. Unfortunately, Karen was forced to quit her job and seek medical help right away.

Sadly, seeking medical help did not make the situation better. The doctors she spoke with stated it must be a gut bacterial infection but insulted her by telling her she must be more hygienic. This catapulted Karen into a very depressive state and Karen was forced to do things differently. For example, Karen now had to get outside jobs where she was not in an enclosed area with coworkers, such as selling flyers around town. To make things worse, Karen was unable to attend both of her sons' high school graduations and has to sleep in a different room than her husband. Karen even told us her family had to leave their house windows open at all times and light candles to mask the smell caused by TMAU.

It wasn’t until 2018 that Karen found out about TMAU. Through RareConnect and other social media platforms, Karen found other TMAU sufferers. Karen then presented all the TMAU information she had researched to medical professionals, but again they insisted she needed to take better showers and even told her she should see a psychologist. Through the years, Karen learned to stay away from certain foods such as yogurt, cheese meat, beans, and milk. These food items would increase her odor. Karen told us she had tried every at home remedy she had seen throughout the internet, including different probiotics and pH soaps, but nothing helped.


During the beginning of this iGEM year, our team had the desire to have a true, meaningful impact on a community in need. We strived to create an impactful and responsible project that would better the world. In December, our team came across trimethylaminuria. After hearing the disheartening stories Karen and all other patients shared with us, we immediately knew this was going to be our project. From there, our team derived a goal: To bring together research/design, along with information brought forth by human practices/stakeholders, to enhance the knowledge of TMAU. By the end of this project, we wanted to ensure the medical community, as well as TMAU patients themselves, knew as much about TMAU as possible. Whether this meant the enzymatic pathways presented in the literature or simply helpful cooking recipes that would ease symptoms, we wanted to make a difference. While our most ambitious goal was to design and develop a probiotic that would eliminate the symptoms of TMAU, we prioritized bringing hope into a broken community and providng the most amount of relief that we could.


[1] Children’s Hospital Colorado. Children’s Hospital Colorado. (n.d.). https://www.childrenscolorado.org/

[2] De Belly, H., Boldt, J., Boulas, I., Cardon, M., Czerwinska, U., Evans, A., Garcia, J. M., Garcia-Timermans, C., Jain, A., Matysiak, M., Castillo, E. M., Rambabu, N., Rousset, F., Satin, P.-L., Larrauri, A. V., & Yang, S. (n.d.). The Smell of Us. https://2014.igem.org/Team:Paris_Bettencourt

[3] Mackay, R. J., McEntyre, C. J., Henderson, C., Lever, M., & George, P. M. (2011, February). Trimethylaminuria: Causes and Diagnosis of a Socially Distressing Condition. National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3052392/

[4] Messenger, J., Clark, S., Massick, S., & Bechtel, M. (2013, November). A review of trimethylaminuria: (fish odor syndrome) - PMC. National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848652/

[5] r/TMAU. Reddit. (n.d.). https://www.reddit.com/r/TMAU/

[6] Systemic Malodor Disorders Research. The MEBO Blog. (n.d.). https://www.meboblog.com/

[7] Trimethylaminuria ('fish odour syndrome’). NHS . (2021, April 16). https://www.nhs.uk/conditions/trimethylaminuria/#:~:text=Trimethylaminuria%20(TMAU)%20is%20an%20uncommon,are%20things%20that%20can%20help.

[8] Trimethylaminuria (TMAU). RareConnect. (n.d.). https://www.rareconnect.org/en/community/trimethylaminuria

[9] Trimethylaminuria. National Organization for Rare Disorders. (2020, October 21). https://rarediseases.org/rare-diseases/trimethylaminuria/

[10] Your first drink of the night for a better tomorrow. ZBiotics. (n.d.). https://zbiotics.com/