title: 3D pattern of brain abnormalities in Williams syndrome visualized using tensor-based morphometry.
abstract: Williams syndrome (WS) is a neurodevelopmental disorder associated with deletion of approximately 20 contiguous genes in chromosome band 7q11.23. Individuals with WS exhibit mild to moderate mental retardation, but are relatively more proficient in specific language and musical abilities. We used tensor-based morphometry (TBM) to visualize the complex pattern of gray/white matter reductions in WS, based on fluid registration of structural brain images.
  
  
  METHODS
  3D T1-weighted brain MRIs of 41 WS subjects (age [mean+/-SD]: 29.2+/-9.2 years; 23F/18M) and 39 age-matched healthy controls (age: 27.5+/-7.4 years; 23F/16M) were fluidly registered to a minimum deformation target. Fine-scale volumetric differences were mapped between diagnostic groups. Local regions were identified where regional structure volumes were associated with diagnosis, and with intelligence quotient (IQ) scores. Brain asymmetry was also mapped and compared between diagnostic groups.
  
  
  RESULTS
  WS subjects exhibited widely distributed brain volume reductions (approximately 10-15% reduction; P<0.0002, permutation test). After adjusting for total brain volume, the frontal lobes, anterior cingulate, superior temporal gyrus, amygdala, fusiform gyrus and cerebellum were found to be relatively preserved in WS, but parietal and occipital lobes, thalamus and basal ganglia, and midbrain were disproportionally decreased in volume (P<0.0002). These regional volumes also correlated positively with performance IQ in adult WS subjects (age > or = 30 years, P = 0.038).
  
  
  CONCLUSIONS
  TBM facilitates 3D visualization of brain volume reductions in WS. Reduced parietal/occipital volumes may be associated with visuospatial deficits in WS. By contrast, frontal lobes, amygdala, and cingulate gyrus are relatively preserved or even enlarged, consistent with unusual affect regulation and language production in WS.
authors.affiliation: Laboratory of Neuro Imaging, Brain Mapping Division, Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095-7332, USA.
authors.forename: Ming-Chang
authors.initials: MC
authors.lastname: Chiang
authors.forename: Allan L
authors.initials: AL
authors.lastname: Reiss
authors.forename: Agatha D
authors.initials: AD
authors.lastname: Lee
authors.forename: Ursula
authors.initials: U
authors.lastname: Bellugi
authors.forename: Albert M
authors.initials: AM
authors.lastname: Galaburda
authors.forename: Julie R
authors.initials: JR
authors.lastname: Korenberg
authors.forename: Debra L
authors.initials: DL
authors.lastname: Mills
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Toga
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
mesh_terms: D000293:Adolescent; D000328:Adult; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D002648:Child; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007360:Intelligence / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018980:Williams Syndrome / Q000175:diagnosis*