Endocrine Abstracts

Aim: Serum sclerostin levels as an indicator of bone resorption in children with congenital adrenal hyperplasia (CAH) have not been evaluated to date. The aim of this study was to determine the role of osteoprotegerin (OPG) and sclerostin in bone metabolism in children with CAH.

Methods: Thirty-one patients (19 girls, 12 boys) with CAH (aged 11.6±3.7 years) and 31 healthy children (age- and sex-matched) as controls were included in the study. The patients were using glucocorticoids (GC) for at least six months. Serum levels of OPG, sclerostin, calcium, phosphate, alkaline phosphatase, parathormone, and 25-hydroxy vitamin D were assessed in patients and controls. Bone mineral density was measured by dual energy X-ray absorptiometry (DEXA) of the lumbar spine.

Results: In patients with CAH and controls, the mean lumbar spine bone mineral density were 0.841±0.220 and 0.852±0.202 (P>0.05), respectively, and 70% of the patients and 68% of the controls were pubertal. Serum levels of calcium, phosphate, alkaline phosphatase, and parathormone were not found different in the groups (P>0.05). Serum OPG levels of the patients were significantly higher than the controls (P<0.001). Serum sclerostin levels were higher in pubertal patients than the pubertal controls (p <0.05), but there is no significant difference in prepubertal patients and controls (P>0.05). A positive correlation was found between serum OPG and sclerostin levels in patients, while there was a negative correlation between serum OPG and sclerostin levels in controls. Serum 25-hydroxy vitamin D levels of the patients and controls were 19.2±7.5 ng/ml and 14.2±4.8 ng/ml, respectively (P<0.05).

Conclusions: The role of sclerostin in bone metabolism was investigated for the first time in patients with CAH by the present study. Increased OPG levels in the patients were considered as a compensation mechanism against the tendency of increased bone resorption in these patients. As stated in the literature, serum sclerostin levels decreased with increasing age in healthy children, but the expected decrease was not observed in the pubertal period in the patient group. This can be considered as a finding of increased susceptibility to bone resorption in patients with CAH. In addition, the concomitant increase in serum sclerostin and OPG levels in the patients may be associated with increased bone turnover in CAH, especially in the pubertal period.*This study was supported by TÜBİTAK 1002 Project (No: 221S143)