The work includes four studies which bring innovative contributions to medical practice by addressing two original themes: assessment of local ucMGP and clinical validation of tMGP as circulating marker in patients with vascular and osteoarticular calcification. In this respect, combined assessment of ucMGP in serum and synovial fluid could serve as joint inflammatory marker in patients with arthritis. The reference range for tMGP in healthy population was also first established along with the evaluation of tMGP in patients with vascular and osteoarticular pathologies. In terms of vascular pathology was found that MGP originating from the superficial veins of the inferior limb would have a contribution to the total pool of circulating MGP. Moreover, a serum threshold for tMGP was established to discriminate between the presence and absence of calcified minor carotid stenosis in postmenopausal women. Accordingly, serum tMGP could be a straightforward and available screening tool for ectopic calcifications.