Prognostic biomarkers for monitoring bone health in adolescents with 21-hydroxylase deficiency (21OHD) are needed.To assess associations between concentrations of baseline bone turnover markers (BTMs) including osteocalcin (OC) and type-I collagen C-terminal telopeptide (CTX) and changes in lumbar spine bone mineral density (LSBMD) in adolescents with classic 21OHD.A retrospective-prospective study of 33 adolescents with classic 21OHD who had baseline data for LSBMD, bone age (BA), and BTM concentrations.BTM concentrations were converted into z-scores according to BA. We measured LSBMD at the follow-up study visit and calculated the annual percentage change in LSBMD (%∆LSBMD).At baseline, participants (55% female, 79% Tanner 5) had mean (±SD) age of 14.6 ± 3.6 years, BA 16.7 ± 2.9 years, and average glucocorticoid (GC) dose 17.3 ± 5.6 mg/mHigher GC dose and the use of prednisolone were associated with decreased LSBMD accrual in adolescents with 21OHD. CTX z-score independently associated with LSBMD accrual, suggesting its potential for prognostic bone biomarker.
