title: Idiopathic juvenile osteoporosis: a cross-sectional single-centre experience with bone histomorphometry and quantitative computed tomography.
abstract: BACKGROUND
  Idiopathic juvenile osteoporosis (IJO) is a rare condition of poorly understood etiology and pathophysiology that affects otherwise healthy children. This condition is characterized clinically by bone pain and vertebral fractures; spontaneous recovery is observed after puberty in the majority of cases. Although decreased trabecular bone turnover has been noted previously, cortical and trabecular bone characteristics as determined by quantitative computed tomography (QCT) and their relationship to bone histomorphometry are unknown.
  
  
  METHODS
  All children with a clinical diagnosis of IJO who were followed in our center since 1995 and who had undergone at least one diagnostic bone biopsy were included in this cross-sectional analysis.
  
  
  RESULTS
  Fifteen patients (11 males/4 females) with median ages of 5.8 and 10.2 years at first symptoms and at referral, respectively, were included in the analysis. Histomorphometric analysis demonstrated decreased trabecular bone turnover (BFR/BS) in the majority of patients with heterogeneous parameters of trabecular mineralization and volume. QCTresults demonstrated that bone mineral density (BMD) was reduced in both trabecular/lumbar and cortical/femoral bone: Z score: -2.1 (-3.6;-1.0) and -0.9 (-8.2;1.4)in the two compartments, respectively. In the eight patients who underwent both bone biopsy and QCT, cortical BMD was associated with trabecular separation and with trabecular bone formation rate (r = 0.898 and -0.881, respectively, both p < 0.05).
  
  
  CONCLUSIONS
  This series confirms that IJO is characterized by impaired trabecular architecture that can be detected by both bone biopsy and QCT. The association between bone biopsy and QCT results may have implications for diagnosis, treatment, and follow-up of these children.
authors: David Geffen School of Medicine, Division of Pediatric Nephrology, University of California, 10833 Le Conte Boulevard, Los Angeles, CA, USA.
authors: Justine
authors: J
authors: Bacchetta
authors: David Geffen School of Medicine, Division of Pediatric Nephrology, University of California, 10833 Le Conte Boulevard, Los Angeles, CA, USA.
authors: Katherine
authors: K
authors: Wesseling-Perry
authors: Department of Radiology, Hospital Los Angeles, Los Angeles, CA, USA.
authors: Vicente
authors: V
authors: Gilsanz
authors: David Geffen School of Medicine, Division of Pediatric Nephrology, University of California, 10833 Le Conte Boulevard, Los Angeles, CA, USA.
authors: Barbara
authors: B
authors: Gales
authors: David Geffen School of Medicine, Division of Pediatric Nephrology, University of California, 10833 Le Conte Boulevard, Los Angeles, CA, USA.
authors: Renata C
authors: RC
authors: Pereira
authors: David Geffen School of Medicine, Division of Pediatric Nephrology, University of California, 10833 Le Conte Boulevard, Los Angeles, CA, USA.
authors: Isidro B
authors: IB
authors: Salusky
keywords: Bone biopsy; Histomorphometry; Idiopathic juvenile osteoporosis; QCT