Brain Topography

, Volume 22, Issue 3, pp 176–184

Thinning of the Motor–Cingulate–Insular Cortices in Siblings Concordant for Tourette Syndrome

  • Cherine Fahim
  • Uicheul Yoon
  • Paul Sandor
  • Kirk Frey
  • Alan C. Evans
Original Paper

DOI: 10.1007/s10548-009-0105-6

Cite this article as:
Fahim, C., Yoon, U., Sandor, P. et al. Brain Topogr (2009) 22: 176. doi:10.1007/s10548-009-0105-6

Abstract

Fraternal twin studies on normal subjects have demonstrated low heritability (intra-class correlation coefficient) estimates for frontal brain regions (r = 0.43). Here we aimed to investigate the relatedness/similarity estimates of the frontal brain regions in fraternal subjects concordant for Tourette syndrome (TS). We sought to identify regional brain similarities between siblings concordant for TS as an exploratory step towards the identification of potential brain structures involved in the TS phenotype. The identified brain structures may then serve in subsequent molecular genetic and linkage studies. In addition, we regressed cortical thickness and TS clinical severity scores to assess the relation between TS clinical symptoms and cortical structures. Sixteen sibling pairs concordant for TS were scanned using a 1.5 T magnetic resonance imaging scanner (age range 10–25, mean 17.19 ± 4.1). Brain morphology was assessed using the fully automated Civet pipeline at the Montreal Neurological Institute. TS was assessed using the Children’s Yale-Brown Obsessive Compulsive Scale (CY-BOCS), Yale Global Tic Severity Scale (YGTSS) and the Goetz Tic Scale. We report high relatedness/similarity estimates for fraternal siblings concordant for TS (r = 0.86–0.60) in the middle frontal-motor/cingulate/insular cortices. Regression analysis revealed significant negative correlations in the right insula with the YGTSS (r = −0.41, F = 6.09, P < 0.02) and the left cingulated cortex with the (CY-BOCS) (r = −0.35, F = 4.30, P < 0.05). Since previous findings have concluded that normal fraternal siblings are less alike in frontal cortices, the present findings may be attributed to TS. We speculate that the high ICC between siblings and the negative correlation between TS symptoms severity and cortical thickness measurements are related to the disturbances in the maturation of the motor–cingulate–insular cortical neural system that mediate self-regulatory processes. Such delayed maturation may consequently contribute to the development of TS by releasing motor and vocal tics from regulatory control. These findings may have important genetic implications.

Keywords

Tourette syndrome Cortical thickness Neuroimaging Anterior cingulate Insula Motor Similarity Intra class correlations 

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Cherine Fahim
    • 1
    • 2
    • 3
    • 4
    • 5
  • Uicheul Yoon
    • 1
    • 4
  • Paul Sandor
    • 7
  • Kirk Frey
    • 8
  • Alan C. Evans
    • 1
    • 4
    • 6
  1. 1.Department of Neurology and NeurosurgeryMcGill UniversityMontrealCanada
  2. 2.Laboratory for the Experimental Research in Behavior (LERB), Faculty of SSP, Institute of PsychologyUniversity of LausanneLausanneSwitzerland
  3. 3.Department of PsychiatryUniversity of MontrealMontrealCanada
  4. 4.McConnell Brain Imaging Center, Montreal Neurological InstituteMcGill UniversityMontrealCanada
  5. 5.Sainte-Justine Hospital Research CentreMontrealCanada
  6. 6.Department of Biomedical EngineeringMcGill UniversityMontrealCanada
  7. 7.Division of Brain Imaging & Behaviour Systems—Neuroscience Toronto Western Research InstituteUniversity of TorontoTorontoCanada
  8. 8.Departments of Radiology and of Neurology, Mental Health Research InstituteUniversity of MichiganAnn ArborUSA

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