Variants in the flavin-containing monooxygenase 3 (FMO3) gene responsible for trimethylaminuria in a Japanese population

► p.Pro70Leu, p.Ser195Leu, p.Ile441Thr, and p.Thr488Ala of FMO3 were identified. ► Recombinantly expressed FMO3 variants showed abnormal trimethylamine N-oxygenation. ► These missense but rare FMO3 mutations could be causative of trimethylaminuria.