In the PBC cohort, ATX activity was higher in patients with a longer duration of the disease (r = 0.327, P < 0.001; Fig. 2A) and patients with liver cirrhosis (11.6 ± 3.5 vs. 9.1 ± 4.7 nmol mL−1 min−1 in non-cirrhotic stage, P < 0.01; Fig. 2B). This evidence concerns the gene ENPP2 and cirrhosis of liver.