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RAMI Psychiatry Registrars' Prize 2008 Thurs, 13 th March 2008

RAMI Psychiatry Registrars' Prize 2008 Thurs, 13 th March 2008 Dr Frederick Sundram, Lecturer in Psychiatry, Dept of Psychiatry, 1 st Floor Smurfit Building, RCSI Education & Research Centre, Beaumont Hospital, Dublin 9 Email: fsundram@rcsi.ie Telephone: 01-8093740.

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RAMI Psychiatry Registrars' Prize 2008 Thurs, 13 th March 2008

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  1. RAMI Psychiatry Registrars' Prize 2008 Thurs, 13th March 2008 Dr Frederick Sundram, Lecturer in Psychiatry, Dept of Psychiatry, 1st Floor Smurfit Building, RCSI Education & Research Centre, Beaumont Hospital, Dublin 9 Email: fsundram@rcsi.ie Telephone: 01-8093740

  2. White matter microstructure in children with Velocardiofacial Syndrome: A Diffusion Tensor Imaging and Voxel Based Morphometry study. Sundram F1, Murphy DG2, Murphy KC1. 1Dept of Psychiatry, RCSI Education & Research Centre, Beaumont Hospital, Dublin 9. 2Dept of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.

  3. Contents • Introduction • Aims • Methods • Results • Discussion • Conclusion

  4. Introduction • To understand the developmental basis of schizophrenia • Promising approach – abnormalities in young individuals who are likely to be at significantly elevated risk for the illness • permits discovery of possible neurobiological and neurodevelopmental mechanisms of risk for the illness[1] [1] Gottesman, I.I., Gould, T.D., 2003. The endophenotype concept in psychiatry: etymology and strategic intentions. Am J Psychiatry 160, 636– 645.

  5. Examples of high-risk groups: Both parents with schizophrenia Monozygotic twins Velocardiofacial Syndrome Obstetric complications Etc.

  6. Velocardiofacial Syndrome (VCFS) is the most common genetic deletion syndrome[2] and is associated with deletions in the chromosome 22q11 region[3]. • COMT and TBX1 genes [2] Gothelf, D. and P. J. Lombroso (2001). "Genetics of childhood disorders: XXV. Velocardiofacial syndrome." J Am Acad Child Adolesc Psychiatry 40(4): 489-91. [3] Botto LD, May K, Fernhoff PM, Correa A, Coleman K, Rasmussen SA, Merritt RK, O'Leary LA, Wong LY, Elixson EM, Mahle WT, Campbell RM (2003) A population-based study of the 22q11.2 deletion: phenotype, incidence, and contribution to major birth defects in the population. Pediatrics 112:101-7

  7. People with VCFS have much higher rates of schizophrenia spectrum disorders[4] • Up to 25-30% [4]Murphy KC, Jones LA, Owen MJ. High rates of schizophrenia in adults with velo-cardio-facial syndrome. Arch Gen Psych 1999; 56: 940–45.

  8. Schizotypy characterized by peculiarities of thinking, odd beliefs, and eccentricities of appearance, behavior, interpersonal style and thought • confers a much higher risk for the future development of psychosis[5]. [5] Arnold, P. D., J. Siegel-Bartelt, et al. (2001). "Velo-cardio-facial syndrome: Implications of microdeletion 22q11 for schizophrenia and mood disorders." Am J Med Genet 105(4): 354-62.

  9. VCFS provides a unique neurobiological template for understanding the evolution of psychosis[6]. [6] Murphy, K. C. and M. J. Owen (2001). "Velo-cardio-facial syndrome: a model for understanding the genetics and pathogenesis of schizophrenia." Br J Psychiatry 179: 397-402.

  10. People with VCFS also have significant abnormalities in white matter anatomy • White matter volume[7] • White matter integrity/connectivity[8][9] [7] Kates, W. R., C. P. Burnette, et al. (2001). "Regional cortical white matter reductions in velocardiofacial syndrome: a volumetric MRI analysis." Biol Psychiatry 49(8): 677-84. [8] Barnea-Goraly, N., V. Menon, B. Krasnow, A. Ko, A. Reiss and S. Eliez (2003). "Investigation of white matter structure in velocardiofacial syndrome: a diffusion tensor imaging study." Am J Psychiatry 160(10): 1863-9. [9] Simon, T. J., L. Ding, J. P. Bish, D. M. McDonald-McGinn, E. H. Zackai and J. Gee (2005). "Volumetric, connective, and morphologic changes in the brains of children with chromosome 22q11.2 deletion syndrome: an integrative study." Neuroimage 25(1): 169-80.

  11. However…….. • only 2 previous studies in VCFS of white matter microstructural integrity as measured using Diffusion Tensor Imaging (DTI) • Ours is 3rd in the world

  12. Also….. • Relationship between white matter anatomy and schizotypy in VCFS[10]never been specifically investigated in children before. [10] Gruzelier, J. H. (2003). "Theory, methods and new directions in the psychophysiology of the schizophrenic process and schizotypy." Int J Psychophysiol 48(2): 221-45.

  13. Aims We planned to assess within VCFS children and controls: • differences in whole brain white matter microstructure using DTI through DTI group mapping analysis • differences in whole brain white matter volume through structural MRI imaging using Voxel based Morphometry analysis • the relationship of the anatomy of those brain regions which significantly differed in the analyses above to schizotypy scores

  14. Methods Ethics Approval • Provided through the Institute of Psychiatry Research Ethics Committee Subjects • Recruited through 22qDS support group • Behavioural Genetics Clinic, Maudsley Hospital

  15. DNA • Extracted from blood samples collected on all subjects • Fluorescence in situ hybridisation (FISH) (Oncor Inc, Gaithersburg, MD, USA) confirmed 3Mb 22q11 deletion in VCFS cases • Chromosome 22q11 deletion excluded in all controls. Exclusion criteria VCFS clinical phenotype but without the large 3Mb 22q11.2 deletion, a clinically detectable medical disorder known to affect brain structure (e.g. epilepsy), a history of head injury or contraindications to MRI scanning

  16. VCFS cases • 11 children (5 male and 6 female) with clinical features of VCFS, established genetic 22q11 deletion • (mean age: 12years, SD±2.2, range 9-17years; mean FSIQ: 66, SD±8.0, range 56-84). Controls • 12 healthy controls (8 male and 4 female) with a non-deleted 22q11 region, of whom 7 were sibling and 5 non-sibling • (mean age: 13years, SD±2.5, range 9-17years; mean FSIQ: 116, SD±15.9, range 90–141). • None had genetic disorder and all were free of clinical disorders affecting brain anatomy or function.

  17. DTI and structural MRI data were acquired at the same scanning session • 1.5T MRI scanner • Measures of interest were the fractional anisotropy (FA) and volume of white matter • As brain changes are likely to extend over a number of contiguous voxels, non-parametric test statistics incorporating spatial information such as 3D cluster mass (the sum of suprathreshold voxel statistics) were used for both DTI group mapping and Voxel Based Morphometry

  18. Locally developed software at the Institute of Psychiatry - XBAM (http://www.brainmap.co.uk/) measured between group differences at each intracerebral voxel in standard space using an analysis of covariance model (ANCOVA) • Finally, we carried out a post hoc analysis to determine if differences in white matter FA or volume were associated with schizotypy (measured using a previously published scale designed for young people with VCFS[11]) within subjects with VCFS. [11] Campbell, L. E., E. Daly, F. Toal, A. Stevens, R. Azuma, M. Catani, et al. (2006). "Brain and behaviour in children with 22q11.2 deletion syndrome: a volumetric and voxel-based morphometry MRI study." Brain 129(Pt 5): 1218-28.

  19. Results DTI group mapping: FA reduction • FA in VCFS subjects was significantly reduced in the frontal, parietal and temporal lobes of the left hemisphere • Changes localised to the: • ascending projections from the thalamus to the post-central gyrus of the parietal lobe via the posterior limb of the internal capsule and posterior thalamic radiation; • descending projections from the motor cortex of the frontal lobe via the superior region of the corona radiata; • tapetum lateral to the posterior horn of the lateral ventricle; • fronto-parietal course of the arcuate fasciculus (AF)

  20. DTI group mapping: FA increases • However, people with VCFS also had a significantly increased FA • exclusively in the left hemisphere again • in regions that were anatomically more anterior and inferior to the FA decreases described previously • especially in the genu/anterior limb of the internal capsule • anterior and superior portions of the corona radiata and • terminal corpus callosum

  21. Fig. 1: Control group vs. VCFS subject group FA. Ascending 2mm transverse sections; (Radiological convention: L=R, R=L). Orange: FA in controls significantly > VCFS subjects. Blue: FA in VCFS subjects significantly > controls.

  22. Voxel Based Morphometry • Mean global white matter volume did not differ significantly between VCFS children and controls (mean=383ml, SD±35.0ml vs. mean=418ml, SD±62.2ml; p=0.114). • However, significant differences in regional distribution of white matter

  23. People with VCFS had a significant reduction bilaterally in the: • middle cerebellar peduncle of the cerebellum and brainstem; • optic radiation and lingual, middle and inferior occipital gyri; • cuneus and precuneus; • posterior thalamic radiation; • body, genu and tapetum of the corpus callosum; • hippocampus and • paracentral lobule

  24. Also….. • they had a significantly greater proportion of white matter bilaterally in the: • anterior limb of the internal capsule • basal ganglia • cingulum and • body and splenium of the corpus callosum

  25. White Matter Volume in VCFS subjects vs. Controls. (Radiological convention L=R, R=L). Red/Yellow: Volumetric excesses in VCFS. Blue/Purple: Volumetric deficits in VCFS.

  26. Schizotypy correlations • Within VCFS • Analysis of schizotypy correlation with white matter FA and white matter volume • Significant positive correlation (r=0.759, n=7, p=0.048) between increased white matter FA in the left internal capsule

  27. Discussion • FA reduction - regions that may have important effects on the connectivity of a number of neural systems • E.g.tapetum, corona radiata and AF which respectively connect the 1) inferior temporal lobes; 2) corticospinal, corticobulbar and corticopontine tracts and 3) frontal, parietal and temporal lobes within each hemisphere • may underpin some of the cognitive impairments classically reported in the disorder e.g. visuo-spatial, attentional and language deficits

  28. Another factor contributing to these cognitive deficits in VCFS - simultaneous decrease in regional white matter volume at non-frontal sites • e.g. the cerebellum, brainstem, occipital lobes and corpus callosum (body, genu and tapetum) suggesting dysmaturation of the posterior structures of the brain.

  29. Schizotypy correlation  internal capsule • large collection of white matter composed of axons that project chiefly from the thalamus to the cerebral cortex and vice versa • anterior limb especially involved in connectivity with the frontal lobe through fronto-thalamic, thalamo- frontal and cortico-pontine pathways • Schizophrenia studies  reduced FA in these circuits[12] • schizotypy like schizophrenia, may arise from abnormalities in fronto-temporal connectivity [12]Shergill, S. S., R. A. Kanaan, X. A. Chitnis, O. O'Daly, D. K. Jones, S. Frangou, et al. (2007). "A diffusion tensor imaging study of fasciculi in schizophrenia." Am J Psychiatry 164(3): 467-73.

  30. Conclusion • As neuroimaging techniques have matured – shift to examining abnormalities in the ‘connectivity’ of neural systems instead of traditional assessment of ‘lesion of a region’ • Disconnectivity between critical regions in VCFS not only results in cognitive impairment but also a predisposition to psychosis which is mediated through changes in fronto-temporal circuitry • These abnormalities may also be relevant to psychosis in the wider population

  31. References [1] Ottoman, I.I., Gould, T.D., 2003. The endophenotype concept in psychiatry: etymology and strategic intentions. Am J Psychiatry 160, 636– 645. [2] Gothelf, D. and P. J. Lombroso (2001). "Genetics of childhood disorders: XXV. Velocardiofacial syndrome." J Am Acad Child Adolesc Psychiatry 40(4): 489-91. [3] Botto LD, May K, Fernhoff PM, Correa A, Coleman K, Rasmussen SA, Merritt RK, O'Leary LA, Wong LY, Elixson EM, Mahle WT, Campbell RM (2003) A population-based study of the 22q11.2 deletion: phenotype, incidence, and contribution to major birth defects in the population. Pediatrics 112:101-7 [4]Murphy KC, Jones LA, Owen MJ. High rates of schizophrenia in adults with velo-cardio-facial syndrome. Arch Gen Psych 1999; 56: 940–45. [5] Arnold, P. D., J. Siegel-Bartelt, et al. (2001). "Velo-cardio-facial syndrome: Implications of microdeletion 22q11 for schizophrenia and mood disorders." Am J Med Genet 105(4): 354-62. [6] Murphy, K. C. and M. J. Owen (2001). "Velo-cardio-facial syndrome: a model for understanding the genetics and pathogenesis of schizophrenia." Br J Psychiatry 179: 397-402. [7] Kates, W. R., C. P. Burnette, et al. (2001). "Regional cortical white matter reductions in velocardiofacial syndrome: a volumetric MRI analysis." Biol Psychiatry 49(8): 677-84. [8] Barnea-Goraly, N., V. Menon, B. Krasnow, A. Ko, A. Reiss and S. Eliez (2003). "Investigation of white matter structure in velocardiofacial syndrome: a diffusion tensor imaging study." Am J Psychiatry 160(10): 1863-9. [9] Simon, T. J., L. Ding, J. P. Bish, D. M. McDonald-McGinn, E. H. Zackai and J. Gee (2005). "Volumetric, connective, and morphologic changes in the brains of children with chromosome 22q11.2 deletion syndrome: an integrative study." Neuroimage 25(1): 169-80. [10] Gruzelier, J. H. (2003). "Theory, methods and new directions in the psychophysiology of the schizophrenic process and schizotypy." Int J Psychophysiol 48(2): 221-45. [11] Campbell, L. E., E. Daly, F. Toal, A. Stevens, R. Azuma, M. Catani, et al. (2006). "Brain and behaviour in children with 22q11.2 deletion syndrome: a volumetric and voxel-based morphometry MRI study." Brain 129(Pt 5): 1218-28. [12]Shergill, S. S., R. A. Kanaan, X. A. Chitnis, O. O'Daly, D. K. Jones, S. Frangou, et al. (2007). "A diffusion tensor imaging study of fasciculi in schizophrenia." Am J Psychiatry 164(3): 467-73.

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