Trimethylaminuria is a metabolic disorder that occurs when the body is unable to break down certain nitrogen containing compounds such as Trimethlymine. Trimethylamine, which has a fishy odour, is produced in the intestines when certain types of food ( ie : eggs,liver,legumes,fish and some vegetables ) are digested. As Trimethylamine begins to accumulate in the body, it is released in the sweat, urine and reproductive fluids and breath. This leads to the characteristic odour of Trimethylaminuria. Affected individuals do not have any other health problems related to the condition, but the unpleasant odour can results in social and phycological problems. Trimethlymanuria is more common in Women. Research indicates this is due to the higher hormone changes aggreivating the symptoms of the disorder.

Trimethylaminuria is often caused by changes ( Mutations ) in the FMO3 Gene and is inherited in an autosomal recessive manner. Although there is no cure to date, Trimethymanuria is often manged by reducing the amount of Trimthlymine in the body. For example, affected people can modifiy there diet to avoid high evels of Trimthlymine. 





























Trimethylaminuria is charachterised by a fishy odour that occurs when excessive Trimthymine is released in an affected persons sweat,urine,breath. Although some people may have a constant strong odour , most have a moderate which varys in intensity.In Females, symptoms may be more severe before menstruation,after taking oral contraceptive,or around the time of menopause.Affected people typically do not have any additional signs or symptoms and appear healthy. However, the odour can interfere with many aspects of daily life, leading to social and phycological problems.

The conditions listed are symptoms that people with this disease may have. For most diseases,symptoms will vary from person to person. People with the same disease may not have the same symptoms listed.This informations comes from a database called Human Phenotype Ontology (HPO ). The HPO collects information on symptoms which have been described in medical resources.


Anemia - Low number of red blood cells or hemoglobin

Autosomal rcessive Inheritance



Neutropenia - Low Blood Neutrophil count  




Most cases of Trimethlymanuria are caused by changes ( Mutations ) in the FMO3 Gene. This Gene provides the body with the instructions to make an enzyme that is responsible for breaking down certain nitrogen-containing compounds such as Trimethylamine.  Trimethylamine is produced in the intestines when certain types of food ( ie eggs,liver,legumes,fish and some vegetables ) are digested. A mutation in this gene prevents the enzyme from working properly, so it is unable to break down compounds like Trimethylamine.

In some instances, Trimethlymanuria may occur in people who DO NOT have changes in both copies FMO3 Gene. In these people Trimethlymanuria may be caused by having high levels of Trimethylamine due to the presence of  more Trimethylamine - producing bacteria in the gut . High levels of Trimethylamine could also be due to a diet high in foods that create Trimethylamine as they are metabolised ( Broken down ) . In some cases, people with a change in only one copy of the FMO3 Gene may have milder Trimethlymanuria symptoms.


Trimethlymanuria is inherited in an autosomal recessive manner. This means to be affected, a person must have a mutation in both copies of the responsible gene in each cell. The parents of an affected person usually carry one mutated copy of the gene and referred to as carriers. Carriers typically do not show signs or symptoms of the condition, but in some case carriers may have mild symptoms of Trimethlymanuria or have episodes of fish-like odour.  When two carriers of an autosomal recessive condition have children, each child has 25% ( 1 in 4 ) rick to have the condition, a 50% ( 1 in 2 ) risk to be a carrier like each of the parents and 25% chance not to have the condition or be a carrier.


A diagnosis of Trimethlymanuria is often suspected based on the presence of characteristic signs and symptoms. A urine test and genetic test can be ordered to confirm the diagnosis. The urine test measures the level of Trimethylamine in the urine, as the affected individuals would be expected to have high levels of Trimethylamine in the urine.


Although there is no current cure for Trimethlymanuria, the following are some ways to reduce odour symptoms.

Avoidance of foods that contain trimethylamine and its precursors (choline, lecithin, and trimethylamine N-oxide). Trimethylamine is present in high levels in milk obtained from wheat-fed cows. Choline is present in high amounts in: eggs, liver, kidney, peas, beans, peanuts, soy products, brussels sprouts, broccoli, cabbage, and cauliflower. Trimethylamine N-oxide is present in seafood  

  • Low doses of antibiotics. This decreases the amount of trimethylamine that is made by bacteria in the intestines   

  • Laxatives can decrease the amount of time food remains in the intestines and therefore reduce the amount of trimethylamine made   

  • Nutritional supplements (activated charcoal and copper chlorophyllin) can decrease the concentration of trimethylamine in the urine

  • Soaps with a moderate pH (between 5.5 and 6.5) can help remove the secreted trimethylamine from the skin

  • Riboflavin (vitamin B2) supplements can enhance any existing FMO3 enzyme activity (which breaks down trimethylamine)   

People with trimethylaminuria may also find the following to be helpful:

  • Behavioral counseling to help with depression and other psychological symptoms

  • Genetic counseling to better understand how they developed trimethylaminuria and the risks of passing the condition on to their children