Median BDNF concentrations were lowest in healthy controls [5.80 ng/mL (IQR: 4.58–7.54); n = 31], higher in PBC patients without MHE [22.94 ng/mL (IQR: 7.69–40.95); n = 36], and intermediate in those with MHE [15.17 ng/mL (IQR: 11.66–31.65); n = 8]. This evidence concerns the gene BDNF and primary biliary cholangitis.