In the PBC group, before transplantation (0 h), the concentration of FGF21 was 3-fold higher in patients below or equal to 45 years old (676.0 ± 86 pg/mL and 219.8 ± 45 pg/mL, respectively; p < 0.0001) (Figure 5B). This evidence concerns the gene FGF21 and primary biliary cholangitis.