title: Differences of 25-hydroxyvitamin D3 concentrations in children and adults with neurofibromatosis type 1.
abstract: OBJECTIVE
  Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder, frequently associated with reduced bone mineral density. Serum 25-hydroxyvitamin D3 concentrations in NF1 adults are lower than in healthy controls in autumn respectively winter and are inversely correlated with the number of dermal neurofibromas. We investigated 25-hydroxyvitamin D3 levels in children and adults with neurofibromatosis type 1 in winter and summer and compared them to healthy controls to get more pathogenic insights in vitamin D3 metabolism in NF1 patients.
  
  
  METHODS
  NF1 patients were clinically examined and serum 25-hydroxyvitamin D3 concentrations were measured in 58 NF1 adults and 46 children in winter as well as in summer and compared to sex-, age- and month-matched controls.
  
  
  RESULTS
  52 adults suffered from 10 to 5000 dermal neurofibromas, whereas none of the children presented neurofibromas. 25-Hydroxyvitamin D3 increased from winter to summer (mean: 21.0 to 46.5nmol/l) in NF1 adults. This increase was even larger (p=0.0001) than in healthy controls (mean: 50.5 to 60.5nmol/l). However, there were no differences of 25-hydroxyvitamin D3 concentrations in NF1 children and healthy controls both in winter and in summer.
  
  
  CONCLUSIONS
  Only adults with NF1 showed lower 25-hydroxyvitamin D3 levels in winter and summer, which are unlikely due to impaired UV-dependent dermal synthesis, but rather might be caused by an accelerated catabolism.
authors.affiliation: Institute of Clinical Chemistry, University Hospital Hamburg Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. Electronic address: c.schnabel@uke.de.
authors.forename: Claudia
authors.initials: C
authors.lastname: Schnabel
authors.affiliation: Robert Koch Institute, Berlin.
authors.forename: Stefan
authors.initials: S
authors.lastname: Dahm
authors.affiliation: Institute of Clinical Chemistry, University Hospital Hamburg Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Streichert
authors.affiliation: Robert Koch Institute, Berlin.
authors.forename: Wulf
authors.initials: W
authors.lastname: Thierfelder
authors.affiliation: Department of Neurology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Lan
authors.initials: L
authors.lastname: Kluwe
authors.affiliation: Department of Neurology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Victor F
authors.initials: VF
authors.lastname: Mautner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002112:Calcifediol / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009456:Neurofibromatosis 1 / Q000097:blood*; D012621:Seasons; D014808:Vitamin D Deficiency / Q000097:blood; D055815:Young Adult
chemical_list: D002112:Calcifediol
keywords: Neurofibromatosis type 1; Vitamin D3 deficiency