TMAU is an inborn error of metabolism like PKU. However, unlike PKU and other such disorders, TMAU does not result in mental retardation or other immediately dangerous physical problems. What it does do, however, is ruin the lives and happiness of children and others sufferers. Because of mutations on the FMO3 gene, people with TMAU cannot metabolise choline and the other precursors of trimethylamine which is a volatile and extremely strong smelling compound which causes sufferers to have a highly unpleasant body odour that ranges from rotten fish to garbage. View how CHOLINE metabolism is impaired in TMAU.

TMAU is inherited in an autosomal recessive fashion. It is still considered a rare disorder. However, it is much under diagnosed because of ignorance in the medical profession and because sufferers hide in shame. It has been suggested that up to 1% of the population carries the mutations that produce the disorder.