FMO4 and trimethylaminuria: The duplicated regions harbor a total of five protein-coding genes: MROH9 and members of the flavin-containing monooxygenase family, including FMO3 (mutations cause the recessive disorder Trimethylaminuria; MIM 602079), FMO2, FMO1, and FMO4, all located within the chr1_D region (Figures 1B, S4, and S5).