title: GH receptor isoforms and skeletal fragility in acromegaly.
abstract: OBJECTIVE
  Acromegaly is associated with an increased prevalence of vertebral fractures (VFs) in close relationship with GH hypersecretion. Two isoforms of the GH receptor (GHR) have been identified; the two isoforms differ or not by the expression of the protein fragment encoded by exon 3 of the GHR gene. Deletion of the exon 3 may influence the functional properties of the GHR and affect fracture risk in acromegalic patients.
  
  
  METHODS
  A cross-sectional study was designed to investigate the association between the d3-GHR isoform and the prevalence of VFs in patients with acromegaly.
  
  
  METHODS
  In this study, 109 acromegalic patients were included (M/F, 48/61): 73 with controlled/cured acromegaly and 36 with active disease. GHR genotype was assessed in each patient. All patients were evaluated for VFs and bone mineral density at lumbar spine and hip. Serum IGF1 levels and bone metabolism markers were measured. A multivariate analysis was performed to establish risk factors for VFs in our population.
  
  
  RESULTS
  d3-GHR carriers showed an increased prevalence of VFs when compared with patients expressing full-length GHR (35/55 vs 12/54; P<0.001). The association between GHR deletion and VFs was demonstrated both in patients with active disease and in those with controlled/cured disease. Out of 35 patients who were prospectively evaluated, 13 (37.1%) developed incident VFs. The incidence of VFs was significantly higher in patients for whom the GHR gene has been deleted when compared with those harboring the fl gene (P=0.04). In multivariate analysis, male sex (odds ratio (OR), 3.250; P=0.041), IGF1 levels (OR, 1.183; P=0.031), length of active diseases (OR, 1.038; P=0.001), and d3-GHR genotype (OR, 3.060; P=0.015) were all confirmed as risk factors of VFs in our population.
  
  
  CONCLUSIONS
  This study suggests for the first time that exon 3 deletion of GHR may predispose patients with active and controlled acromegaly to a higher risk of VFs.
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Marilda
authors.initials: M
authors.lastname: Mormando
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Luigi A
authors.initials: LA
authors.lastname: Nasto
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Bianchi
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Gherardo
authors.initials: G
authors.lastname: Mazziotti
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Giampietro
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy enrico.pola@rm.unicatt.it.
authors.forename: Enrico
authors.initials: E
authors.lastname: Pola
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Pontecorvi
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Giustina
authors.affiliation: Pituitary UnitDepartment of EndocrinologyDivision of Spine SurgeryDepartment of Orthopaedics and Traumatology, Catholic University School of Medicine, 'A. Gemelli' University Hospital, l.go Agostino Gemelli 8, 00168 Rome, ItalyChair of EndocrinologyUniversity of Brescia, 25125 Brescia, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: De Marinis
mesh_terms: D000172:Acromegaly / Q000150:complications / Q000235:genetics*; D000328:Adult; D000368:Aged; D015519:Bone Density / Q000235:genetics; D003430:Cross-Sectional Studies; D005091:Exons; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000235:genetics; D011986:Receptors, Somatotropin / Q000235:genetics*; D016103:Spinal Fractures / Q000453:epidemiology / Q000235:genetics*
chemical_list: C583557:IGF1 protein, human; D020033:Protein Isoforms; D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I