In addition, obesity, alkaline phosphatase, co-administered drugs and other single nucleotide polymorphisms such as the SLCO1B3, SLCO1B1, SLC22A6, ABCB1, ABCG2, SLCO3A1, ABCC2, SLC22A1, ABCB11 and NR1I2 genes, have been reported to be associated with decreased metabolism of voriconazole to its inactive N-oxide metabolite [31,32,42,43]; however, these additional confounders were not assessed in our study. Here, ABCB1 is linked to obesity due to melanocortin 4 receptor deficiency.