22q11.2 Deletion Syndrome Is Associated with Altered Resting State Networks

Thursday, May 12, 2016: 11:30 AM-1:30 PM
Hall A (Baltimore Convention Center)
C. M. Pretzsch1, E. Daly2, C. M. Murphy2, C. Ecker2, G. M. McAlonan3, M. Gudbrandsen2, R. H. Wichers2, L. Kushan4, C. Bearden5, M. Craig2 and D. G. Murphy2, (1)Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom, (2)Sackler Institute for Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences,, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom, (3)Department of Forensic and Neurodevelopmental Science, IoPPN, KCL, London, United Kingdom, (4)Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, (5)Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, CA
Background: The biological basis of Autism Spectrum Disorder (ASD) is still not fully understood. The study of conditions with a clearly identified genetic risk for neurodevelopmental disorders, such as 22q11.2 deletion syndrome (22q11DS), may help identify important biological pathways which are intermediate between risk genes and disorder. Therefore, we tested the hypothesis that the 22q11.2 deletion would impact upon the functional integrity of core resting state networks in brain.

Objectives: Functional magnetic resonance imaging (fMRI) was used to investigate neural resting state networks (RSNs) in the brain at rest in individuals with and without 22q11DS. This study had two aims: (1) To identify RSNs shared among individuals with 22q11DS and healthy controls: These RSNs were predicted to be in line with those established by previous research. (2) A between-group comparison of RSNs: Significant group-differences across widespread RSNs were predicted.

Methods: Thirteen individuals with 22q11DS and 34 healthy controls matched for age and sex underwent resting state fMRI. The data were analysed using spatial independent component analysis (Infomax algorithm). One-sample and two-sample t-tests were used to identify across-group networks and between-group differences, respectively. Although groups were matched on age, as brain maturation trajectories can be quite distinct in neurodevelopmental disorders, beta-values from regions of significant group-differences were also extracted and potential correlations with participants’ ages were explored.

Results: Recognised RSNs were identified in all participants, including the Anterior Salience, Auditory, Default Mode (dorsal and ventral part), Higher Visual, Language, Left Executive Control, Primary Visual, and Visuospatial Network. All RSNs except for the ventral part of the Default Mode Network showed significant between-group differences, which were similar to differences reported in studies of idiopathic neurodevelopmental conditions. There was no effect of age in either group.

Conclusions: 22q11DS alters RSNs. This may constitute an intermediate phenotype and further analyses will examine the possible clinical correlates of these differences.