BONE-RESORPTION ASSESSED BY IMMUNOASSAY OF URINARY CROSS-LINKED COLLAGEN PEPTIDES IN PATIENTS WITH OSTEOGENESIS IMPERFECTA

Urinary excretion of type I collagen cross-linked N-telopeptides was s tudied in 52 children and adolescents with osteogenesis imperfecta (OI ) and found to be above the 75th percentile of controls in 44 of the p atients. OI patients suffering from fractures during the preceding 6 m onths had significantly higher values (p < 0.05). In contrast, patient s with better motor performance tended to have lower values (p = 0.059 ). The concentration of urinary type I collagen cross-linked N-telopep tides was positively correlated with urinary calcium excretion (p < 0. 05), which was found to be elevated in 20 of the patients. Our results show that during childhood and adolescence in OI not only the synthes is but also the turnover of mature cross-linked type I collagen is dis turbed and provide evidence that bone resorption rates are elevated.