title: Tibial geometry in individuals with neurofibromatosis type 1 without anterolateral bowing of the lower leg using peripheral quantitative computed tomography.
abstract: BACKGROUND
  Lower leg bowing with tibial pseudarthrosis is associated with neurofibromatosis type 1 (NF1). The objective of the study is to determine if the geometry of the lower limb in individuals with neurofibromatosis type 1 (NF1) differs from controls, and to characterize the osseous components of the tibia in NF1.
  
  
  METHODS
  Peripheral quantitative computed tomography (pQCT) of the lower limb was performed (90 individuals with NF1 without tibial and/or fibular dysplasia: 474 healthy individuals without NF1). Subjects were 4-18 years of age. Individuals with NF1 were compared to controls using an analysis-of-covariance with a fixed set of covariates (age, weight, height, Tanner stage, and gender).
  
  
  RESULTS
  Using pQCT, NF1 individuals without bowing of the lower leg have smaller periosteal circumferences (p<0.0001), smaller cortical area (p<0.0001), and decreased tibial cortical and trabecular bone mineral content (BMC) (p<0.0001) compared to controls.
  
  
  CONCLUSIONS
  Individuals with NF1 have a different geometry of the lower leg compared to healthy controls suggesting that NF1 haploinsufficiency impacts bone homeostasis although not resulting in overt anterolateral bowing of the lower leg.
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, University of Utah, SLC, UT 84132, USA. david.stevenson@hsc.utah.edu
authors.forename: David A
authors.initials: DA
authors.lastname: Stevenson
authors.forename: David H
authors.initials: DH
authors.lastname: Viskochil
authors.forename: John C
authors.initials: JC
authors.lastname: Carey
authors.forename: Hillarie
authors.initials: H
authors.lastname: Slater
authors.forename: Mary
authors.initials: M
authors.lastname: Murray
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Sheng
authors.forename: Jacques
authors.initials: J
authors.lastname: D'Astous
authors.forename: Heather
authors.initials: H
authors.lastname: Hanson
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Schorry
authors.forename: Laurie J
authors.initials: LJ
authors.lastname: Moyer-Mileur
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007866:Leg / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D009456:Neurofibromatosis 1 / Q000000981:diagnostic imaging* / Q000473:pathology*; D013977:Tibia / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed