EVALUATION OF CIRCULATING TYPE-I PROCOLLAGEN PROPEPTIDES IN PATIENTS WITH PAGETS-DISEASE OF BONE

We evaluated circulating aminoterminal and carboxyterminal propeptides of type I procollagen and total alkaline phosphatase levels in eighty consecutive patients affected by Paget's disease of bone. We compared the biochemical data with the extent of bone disease calculated on th e basis of the bone scintigraphic indices. Serum aminoterminal propept ide of type I procollagen levels were high in 77% of patients, serum c arboxyterminal propeptide of type I procollagen levels in 22% and seru m total alkaline phosphatase levels in 76%. We found significant corre lations between the three markers studied. The three biochemical marke rs correlated significantly with the bone scintigraphic activity indic es, but the highest correlation coefficient was between the aminotermi nal propeptide and total alkaline phosphatase. We conclude that there is a discrepancy between serum levels of the propeptides studied in re lation to Paget's disease of bone. The sensitivity of the carboxytermi nal propeptide of type I procollagen in this disease is low. In contra st the aminoterminal propeptide may be as sensitive a marker for the e valuation of this disorder as total alkaline phosphatase, and in addit ion may be more specific.