Additionally, in disease pathogenesis, the nucleotide-binding oligomerization domain-containing protein 2 (NOD2) gene, a risk allele for inflammatory bowel disease, is associated with the concentration of Lactobacillus and Bacteroides uniformis in the gut, whereas in primary sclerosing cholangitis, the fucosyltransferase 2 (FUT2) gene is associated with the concentration of Firmicutes and Proteobacteria in the bile (11, 12). Here, NOD2 is linked to sclerosing cholangitis.