Serum 24,25-dihydroxyvitamin D concentrations in osteogenesis imperfecta: relationship to bone parameters.
BACKGROUND
Several studies suggest that 24,25-dihydroxyvitamin D [24,25(OH)₂D] may have an effect on bone mass and metabolism.


OBJECTIVE
We evaluated the relationship between serum 24,25(OH)₂D levels and bone density and bone metabolism in children with a primary bone disorder-osteogenesis imperfecta (OI).


METHODS
The study included 132 patients (age, 1.1 to 17.9 yr; 67 girls) with OI types I, III, or IV who had not received bisphosphonate treatment at the time of analysis.


RESULTS
Serum 24,25(OH)₂D levels were significantly higher in OI type III than in OI type I or IV. Serum 24,25(OH)₂D concentrations were positively correlated with serum 25-hydroxyvitamin D (25OHD) levels and negatively correlated with serum PTH levels, and were not correlated with serum 1α,25-dihydroxyvitamin D [1,25(OH)₂D]. The ratio between serum 24,25(OH)₂D and 25OHD was negatively correlated with age and was independent of serum 25OHD concentrations. Regression analysis revealed that OI severity (P = 0.04), serum 25OHD levels (P < 0.001), and serum PTH concentrations (P = 0.045), but not age, gender, or serum 1,25(OH)₂D, were independent predictors of serum 24,25(OH)₂D levels. No correlation was found between serum 24,25(OH)₂D levels or the ratio between serum 24,25(OH)₂D and 25OHD and lumbar spine bone mineral density z-scores or bone marker levels (serum osteocalcin and urinary collagen type I N-telopeptide) after adjusting for OI type, age, and gender.


CONCLUSIONS
Patients with more severe OI type had higher 24,25(OH)₂D serum levels and higher serum 24,25(OH)₂D to 25OHD ratios, suggesting an increased 25OHD-24-hydroxylase activity.
Genetics Unit, Shriners Hospital for Children, 1529 Cedar Avenue, Montréal, Québec, Canada H3G 1A6.
Thomas
T
Edouard
Abdallah
A
Husseini
Francis H
FH
Glorieux
Frank
F
Rauch
D015650:24,25-Dihydroxyvitamin D 3 / Q000097:blood*; D015652:25-Hydroxyvitamin D 2 / Q000097:blood; D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism*; D002112:Calcifediol / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004872:Ergocalciferols / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010013:Osteogenesis Imperfecta / Q000097:blood* / Q000378:metabolism* / Q000503:physiopathology / Q000652:urine; D010281:Parathyroid Hormone / Q000097:blood; D012189:Retrospective Studies; D012720:Severity of Illness Index
D015650:24,25-Dihydroxyvitamin D 3; D015652:25-Hydroxyvitamin D 2; D015415:Biomarkers; D002112:Calcifediol; D004872:Ergocalciferols; D010281:Parathyroid Hormone; C470125:PTH protein, human; C028140:24,25-dihydroxyvitamin D2