Frontiers The role of trimethylamine N oxide in disease pathogenesis and the therapeutic potential of traditional Chinese medicine Breakthrough in studying the enzyme that ultimately produces fish odour syndrome Scientists make breakthrough in studying the enzyme involved in fish odor syndrome Trimethylaminuria: FMO3 mutations that cause malodorous body odor Trimethylaminuria, or fish odour syndrome is an uncommon condition that causes an unpleasant, fishy smell. The body is unable to turn a strong smelling chemical called trimethylamine produced in the gut when