title: Low bone mineral mass is associated with decreased bone formation and diet in girls with Rett syndrome.
abstract: OBJECTIVE
  The aim of the present study was to characterize biomarkers of bone turnover and their relation with bone mineral mass in a cross-sectional cohort of girls with Rett syndrome (RTT) and to examine the role of dietary, biochemical, hormonal, and inflammatory factors on bone mineral mass and bone biomarkers in this disorder.
  
  
  METHODS
  Total body bone mineral content (BMC) and bone mineral density (BMD) were determined by dual-energy x-ray absorptiometry. Dietary nutrient intakes were determined from 3-day food records. Biomarkers of bone turnover, bone metabolites, vitamin D metabolites, hormones, and inflammatory markers were measured by standard clinical laboratory methods.
  
  
  RESULTS
  Serum osteocalcin, bone alkaline phosphatase, and C-telopeptide showed significant inverse relations with age in the RTT cohort. Mean osteocalcin concentrations were significantly lower and mean bone alkaline phosphatase concentrations were significantly higher for individual age groups in the RTT cohort than mean values for their respective age ranges in the reference population. Significant inverse associations were identified between urinary calcium losses, expressed as calcium:creatinine ratios, and total body BMC and BMD z scores. Dietary protein, calcium, and phosphorus intakes, expressed as a proportion of Dietary Reference Intakes for age and sex, showed significant positive associations with total body BMD z scores.
  
  
  CONCLUSIONS
  The present study suggests decreased bone formation instead of increased bone resorption may explain in part the deficits in bone mineral mass in RTT and that attention to the adequacy of dietary protein, calcium, and phosphorus intakes may offer an opportunity to improve bone health in RTT.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, Houston, TX.
authors.forename: Kathleen J
authors.initials: KJ
authors.lastname: Motil
authors.forename: Judy O
authors.initials: JO
authors.lastname: Barrish
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Neul
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Glaze
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000469:Alkaline Phosphatase / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D001842:Bone and Bones / Q000503:physiopathology*; D002136:Calcium, Dietary; D002648:Child; D002675:Child, Preschool; D024042:Collagen Type I / Q000097:blood*; D003430:Cross-Sectional Studies; D004032:Diet; D015930:Diet Records; D004044:Dietary Proteins; D005260:Female; D006801:Humans; D009929:Organ Size; D015675:Osteocalcin / Q000097:blood*; D010012:Osteogenesis; D010455:Peptides / Q000097:blood*; D016226:Phosphorus, Dietary; D015518:Rett Syndrome / Q000473:pathology / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002136:Calcium, Dietary; D024042:Collagen Type I; D004044:Dietary Proteins; D010455:Peptides; D016226:Phosphorus, Dietary; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D000469:Alkaline Phosphatase