FMO3 and trimethylaminuria: Finally, hepatic FMO3 is the primary FMO responsible for trimethylamine N-oxide (TMAO) production from trimethylamine, so that genetic mutations affecting the production or activity of FMO3 result in the disorder trimethylaminuria (or fish-odour syndrome) (Dolphin et al. 1997; Yamazaki and Shimizu 2007; Shephard et al. 2012; Phillips and Shephard 2020).