title: Temporal and occipital lobe features in children with hypochondroplasia/FGFR3 gene mutation.
abstract: BACKGROUND
  Thanatophoric dysplasia (TD) and hypochondroplasia are both caused by FGFR3 (fibroblast growth factor receptor 3) gene mutations. Temporal lobe dysplasia has been well described in thanatophoric dysplasia; however, only a couple of anecdotal cases of temporal lobe dysplasia in hypochondroplasia have been described.
  
  
  OBJECTIVE
  To define temporal lobe abnormalities in patients with hypochondroplasia, given that they share the same genetic mutation.
  
  
  METHODS
  We identified brain imaging studies of nine children with hypochondroplasia. The temporal lobes were assessed on CT and MRI for size and configuration of the temporal horn and aberrant sulcation of the inferior surface of the temporal lobe.
  
  
  RESULTS
  All children had a triangular-shape temporal horn and deep transverse fissures of the inferior temporal lobe surface. Neuroimaging in our cohort revealed enlarged temporal lobes and oversulcation of the mesial temporal and occipital lobes, with abnormal inferomedial orientation of these redundant gyri. Hippocampal dysplasia was also universal.
  
  
  CONCLUSIONS
  We confirmed frequent inferomesial temporal and occipital lobe abnormalities in our cohort of children with hypochondroplasia. Murine models with mutant fgfr3 display increased neuroprogenitor proliferation, cortical thickness and surface area in the temporo-occipital cortex. This is thought to result in excessive convolution and likely explains the imaging findings in this patient cohort. (Note that fgfr3 is the same genetic mutation in mice as FGFR3 is in humans.).
authors: Department of Neuroradiology, The Hospital for Sick Children, Toronto, ON, Canada. cristina.philpott@sickkids.ca
authors: Cristina M
authors: CM
authors: Philpott
authors: Elysa
authors: E
authors: Widjaja
authors: Charles
authors: C
authors: Raybaud
authors: Helen M
authors: HM
authors: Branson
authors: Peter
authors: P
authors: Kannu
authors: Susan
authors: S
authors: Blaser
mesh_terms: D000293:Adolescent; D001842:Bone and Bones / Q000002:abnormalities*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004392:Dwarfism / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D017880:Limb Deformities, Congenital / Q000175:diagnosis* / Q000235:genetics*; D008141:Lordosis / Q000175:diagnosis* / Q000235:genetics*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009154:Mutation / Q000235:genetics; D009778:Occipital Lobe / Q000000981:diagnostic imaging / Q000473:pathology*; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: C496365:FGFR3 protein, human; D051498:Receptor, Fibroblast Growth Factor, Type 3
references: Dev Biol. 2005 Mar 1;279(1):73-85
references: 15708559
references: Endocr Rev. 2000 Feb;21(1):23-39
references: 10696568
references: Ultrasound Obstet Gynecol. 2010 Nov;36(5):582-95
references: 20499405
references: Acta Neuropathol. 2005 Sep;110(3):208-21
references: 16133544
references: Am J Med Genet A. 2003 Jul 1;120A(1):88-91
references: 12794698
references: Am J Med Genet A. 2005 Nov 1;138(4):389-91
references: 16222682
references: Neural Dev. 2009 Feb 03;4:4
references: 19192266
references: Dev Growth Differ. 2009 Apr;51(3):299-323
references: 19379279
references: Childs Nerv Syst. 1991 Feb;7(1):21-6
references: 2054803
references: AJR Am J Roentgenol. 2009 Jan;192(1):48-51
references: 19098178
references: Pediatr Neurosci. 1988;14(4):169-76
references: 3269536
references: J Child Neurol. 2007 Feb;22(2):211-3
references: 17621485