Trimethylaminuria: MedlinePlus Genetics (2024)

FAQs

Trimethylaminuria: MedlinePlus Genetics? ›

If the enzyme is missing or its activity is reduced because of a variant in the FMO3 gene, trimethylamine is not processed properly and can build up in the body. As excess trimethylamine is released in a person's sweat, urine, and breath, it causes the odor characteristic of trimethylaminuria.

How trimethylaminuria is inherited. Many people with trimethylaminuria inherit a faulty version of a gene called FMO3 from both their parents. This means they have 2 copies of the faulty gene. The parents themselves might only have 1 copy of the faulty gene.

Trimethylaminuria is caused by mutations of the FMO3 gene in a North American cohort.

Trimethylaminuria (TMAU) is a rare metabolic disorder resulting in the accumulation of trimethylamine. Primary TMAU is an autosomal recessive genetic condition that results in the deficiency or dysfunction of the hepatic enzyme flavin monooxygenase 3.

Factors such as food, drink, gut microbiome, and genetics can affect body odor.

Primary trimethylaminuria is inherited in an autosomal recessive manner. The parents of an affected individual are obligate heterozygotes (i.e., presumed to be carriers of one FMO3 pathogenic variant based on family history).

Yes, just like typical body odor or sweat, people with TMAU may notice how they smell. But like typical body odor or sweat, some people with this condition may be accustomed to the smell and less likely to react to it than people around them. That being said, not everyone with this condition notices anything unusual.

The symptoms of trimethylaminuria can be improved by changes in the diet to avoid precursors, in particular TMAO which is found in high concentrations in marine fish. Treatment with antibiotics to control bacteria in the gut, or activated charcoal to sequester TMA, may also be beneficial.

Trimethylamine is initially generated by gut bacteria as a by-product of the metabolism of dietary nutrients such as choline. Trimethylamine is then eliminated in many host species (including humans and rats) by a liver and kidney catabolism enzyme (flavin monooxygenase 3 or FMO3).

Chemical and dietary precursors of trimethylamine

Examination of the precursor chemicals for trimethylamine contamination revealed the following results (in ppm; μg/g); betaine 0.2, carnitine 2.5, choline 11.6, creatinine 0.2, lecithin 0.5, trimethylamine N-oxide 0.5.

What neutralizes trimethylamine? ›

When citric acid reacts with Trimethylamine, a weak base, they undergo a neutralization reaction, forming a salt that does not have the fishy odor. This reaction helps to neutralize the smell by breaking down the basic compound that causes the odor, effectively masking the fishiness.

Trimethylaminuria, better known as fish odor syndrome, is a psychologically disabling condition in which a patient emits a foul odor, which resembles that of rotting fish.

In rare cases, a fishy odor may be the result of an inherited condition called trimethylaminuria. Your body naturally produces trimethylamine (TMA) when breaking down certain foods. The strong-smelling chemical generally breaks down into a less fragrant compound, allowing your body to excrete TMA without notice.

Is trimethylaminuria inherited? Yes. Trimethylaminuria is usually inherited in an autosomal recessive fashion, which means that two non-functioning FMO3 genes are usually needed for a person to have symptoms.

While only 2 percent of Europeans lack the genes for smelly armpits, most East Asians and almost all Koreans lack this gene, Day told LiveScience.

ABCC11: the “no body odor gene”

Genetic variants that cause a loss of function of the ABCC11 gene are very common among East Asian ethnicities (80-90% of the population). In other population groups, it is rare to have no body odor. In fact, only around 2% of Caucasians carry the 'no body odor' version of the gene.

Trimethylamine is initially generated by gut bacteria as a by-product of the metabolism of dietary nutrients such as choline. Trimethylamine is then eliminated in many host species (including humans and rats) by a liver and kidney catabolism enzyme (flavin monooxygenase 3 or FMO3).

TMAU is diagnosed by measuring the TMAO:TMA ratio in the urine. In normal subjects, 80% of the TMA is oxidized and then excreted mainly in the urine; in individuals with TMAU, less than 25% of the TMA is oxidized [2, 3].

sem*n has a faint smell that varies from person to person. Lasting changes to the smell of sem*n can be a sign of an underlying medical condition. For example, a strong foul or fishy smell can be a sign of infection or a sexually transmitted condition. See a doctor if these changes occur.