Serum bone GLA-protein is not a sensitive marker of bone turnover in Paget's disease of bone.

Serum bone Gla-protein (sBGP) was measured in 32 patients with untreated Paget's disease of bone. Despite clinical and biological symptoms of active disease in all patients, sBGP was normal in 13/32 patients (41%). There was a striking discrepancy between the moderate increase of sBGP above normal values (11.4 +/- 4.5 vs 6.0 +/- 2.1 ng/ml) and the marked increase of both serum alkaline phosphatase (sAP) and urinary hydroxyproline (uOHP). sBGP was weakly correlated with sAP (r = 0.50, p less than 0.01), uOHP (r = 0.48, p less than 0.01) and with the extension of the disease (r = 0.48, p less than 0.01). We conclude that sBGP is not a sensitive marker of bone turnover in patients with Paget's disease of bone, and should be interpreted with caution in this condition.