For instance, a prospective study on 104 patients with primary hyperparathyroidism revealed higher P1NP (73.5 versus 49.2 ng/mL, p = 0.005), osteocalcin (37.4 versus 23.5 ng/mL, p = 0.02), and CTX levels (0.68 versus 0.38 ng/mL, p = 0.001) in hypercalcaemic versus normocalcemic variant [35]. Here, CYP27A1 is linked to primary hyperparathyroidism.