We conducted semiautomated, atlas-based analyses of regional brain volume changes on MRIs of children and adolescents with Down syndrome (DS) (N=15), DS with comorbid autism spectrum disorder (ASD) (N=15), and age-matched or sex-matched typically developing controls (N=22). Selective volumetric changes were correlated with neurobehavioral measures to determine their functional significance. DS involved selective reduction of frontal and parietal gray matter volumes, beyond the global microencephaly typically observed in this condition. DS with comorbid ASD involved relative hyperplasia of white matter in the cerebellum and brainstem compared with DS only. Cerebellar white matter volumes were positively correlated with severity of stereotypies, a distinctive feature of ASD in DS.
aCenter for Genetic Disorders of Cognition and Behavior, Kennedy Krieger Institute
bDepartments of Pediatrics
cPathology, Neurology, Psychiatry and Behavioral Sciences, and Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
Correspondence to Walter E. Kaufmann, MD, Center for Genetic Disorders of Cognition and Behavior, Kennedy Krieger Institute, 3901 Greenspring Ave., Baltimore, MD 21211, USA
Tel: +1 443 923 7600; fax: +1 443 923 7696; e-mail: email@example.com
Received 3 October 2007; accepted 5 November 2007