SERUM LEVELS OF THE PYRIDINOLINE CROSS-LINKED CARBOXYTERMINAL TELOPEPTIDE OF TYPE-I COLLAGEN (ICTP) AND OSTEOCALCIN IN RACHITIC CHILDREN INNIGERIA

Objectives: We measured the levels of the pyridinoline crosslinked car boxyterminal telopeptide of type I collagen (ICTP) and osteocalcin (OC ) in the serum of 12 rachitic and 27 healthy Nigerian children, and co mpared the performance of these relatively new markers of bone metabol ism with established laboratory parameter of skeletal disease. Design and Methods: Active rickets was diagnosed on the basis of clinical and biochemical criteria. Serum calcium and phosphorus concentration and alkaline phosphatase activity were determined using clinically accepte d methods. Radioimmuno-assay was performed to quantify parathyroid hor mone, 1-25-dihydroxyvitamin D, OC, and ICTP. Results: The rachitic chi ldren had statistically significant serum elevations of ICTP and osteo calcin as compared with age- and sex-matched controls. Serum levels of ICTP correlated with alkaline phosphate activity. Conclusions: As a m arker of abnormal bone metabolism, ICTP performs at least as well as a lkaline phosphate. ICTP and OC are valuable additions to the growing r epertoire of bone markers.