Biochemical bone markers in the assessment and pamidronate treatment of children and adolescents with osteogenesis imperfecta.

AIM: To assess the role of biochemical bone markers in classification of children with osteogenesis imperfecta (OI), their possible association with vertebral compression fractures in milder forms of OI and their role in monitoring of intravenous pamidronate (APD) treatment.
METHODS: Serum total alkaline phosphatase (ALP), bone ALP isoforms (in a subgroup), osteocalcin, type I procollagen carboxy-terminal propeptide, carboxy-terminal telopeptide of type I collagen, and urine deoxypyridinoline (DPD) were measured in a cross-sectional study of 130 untreated individuals, 0.25-20.9years (median 6.7), with OI types I, III and IV. Of those, sixty-nine were also assessed longitudinally during monthly APD treatment. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry.
RESULTS: Significant differences in bone markers, however not sufficient for individual clinical use, were found in the larger untreated group but not between subgroups with or without vertebral compressions. All bone markers decreased during treatment for 1.0-12.5years, but with different relative amounts. Changes were not correlated to the improvement in BMD, mobility or pain.
CONCLUSION: Bone markers are, despite significant differences, not useful for the classification of OI type in the individual child and are not associated with vertebral compressions. Serum ALP and urinary DPD are sensitive in monitoring bisphosphonate treatment.