In addition, due to a decrease in the circulation of 1,25(OH)2 vitamin D secondary to a compromised liver production of vitamin D 25-hydroxylase, calcium intestinal absorption is reduced, and secondary hyperparathyroidism develops, which, in turn, favours cardiovascular metastatic calcifications in patients with liver cirrhosis [34]. Here, CYP2R1 is linked to secondary hyperparathyroidism.