Browsing by Author "Heung, Tracy"
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Item Genetic contributors to risk of schizophrenia in the presence of a 22q11.2 deletion(2020) Cleynen, Isabelle; Engchuan, Worrawat; Hestand, Matthew; Heung, Tracy; Holleman, Aarón M.; Johnston, Richard; Monfeuga, Thomas; McDonald McGinn, Donna M.; Gur, Raquel E.; Morrow, Bernice E.; Swillen, Ann; Vorstman, Jacob A. S; Bearden, Carrie E.; Chow, Eva W. C.; van den Bree, Marianne; Emanuel, Beverly S.; Vermeesch, Joris R.; Warren, Stephen T.; Owen, Michael J.; Chopra, Pankaj; Cutler, David J.; Duncan, Richard; Kotlar, Alex V.; Mulle, Jennifer G.; Voss, Anna J.; Zwick, Michael E.; Diacou, Alexander; Golden, Aaron; Guo, Tingwei; Lin, Jhih Rong; Wang, Tao; Zhang, Zhengdong; Zhao, Yingjie; Marshall, Marshall; Merico, Daniele; Jin, Andrea; Lilley, Brenna; Salmons, Harold I.; Oanh, Tran; Pardinas, Antonio; Repetto, GabrielaSchizophrenia occurs in about one in four individuals with 22q11.2 deletion syndrome (22q11.2DS). The aim of this International Brain and Behavior 22q11.2DS Consortium (IBBC) study was to identify genetic factors that contribute to schizophrenia, in addition to the ~20-fold increased risk conveyed by the 22q11.2 deletion. Using whole-genome sequencing data from 519 unrelated individuals with 22q11.2DS, we conducted genome-wide comparisons of common and rare variants between those with schizophrenia and those with no psychotic disorder at age ≥25 years. Available microarray data enabled direct comparison of polygenic risk for schizophrenia between 22q11.2DS and independent population samples with no 22q11.2 deletion, with and without schizophrenia (total n = 35,182). Polygenic risk for schizophrenia within 22q11.2DS was significantly greater for those with schizophrenia (padj = 6.73 × 10−6 ). Novel reciprocal case–control comparisons between the 22q11.2DS and population-based cohorts showed that polygenic risk score was significantly greater in individuals with psychotic illness, regardless of the presence of the 22q11.2 deletion. Within the 22q11.2DS cohort, results of gene-set analyses showed some support for rare variants affecting synaptic genes. No common or rare variants within the 22q11.2 deletion region were significantly associated with schizophrenia. These findings suggest that in addition to the deletion conferring a greatly increased risk to schizophrenia, the risk is higher when the 22q11.2 deletion and common polygenic risk factors that contribute to schizophrenia in the general population are both presentItem Rare Genome-Wide Copy Number Variation and Expression of Schizophrenia in 22q11.2 Deletion Syndrome(American Psychiatric Association, 2017) Bassett, Anne; Lowther, Chelsea; Merico, Daniele; Costain, Gregory; Chow, Eva; van Amelsvoort, Therese; McDonald-McGinn, Donna; Gur, Raquel; Swillen, Ann; Van den Bree, Marianne; Murphy, Kieran; Gothelf, Doron; Bearden, Carrie; Eliez, Stephan; Kates, Wendy; Philip, Nicole; Sashi, Vandana; Campbell, Linda; Vorstman, Jacob; Cubells, Joseph; Repetto, Gabriela; Simon, Tony; Boot, Erik; Heung, Tracy; Evers, Rens; Vingerhoets, Claudia; van Duin, Esther; Zackai, Elaine; Vergaelen, Elfi; Devriendt, Koen; Vermeesch, Joris; Owen, Michael; Murphy, Clodagh; Michaelovosky, Elena; Kushan, Leila; Schneider, Maude; Fremont, Wanda; Busa, Tiffany; Hooper, Stephen; McCabe, Kathryn; Duijff, Sasja; Isaev, Karin; Pellecchia, Giovanna; Wei, John; Gazzellone, Matthew; Scherer, Stephen; Emanuel, Beverly; Guo, Tingwei; Morrow, Bernice; Marshall, Christian; International 22q11.2DS Brain and Behavior ConsortiumOBJECTIVE: Chromosome 22q11.2 deletion syndrome (22q11.2DS) is associated with a more than 20-fold increased risk for developing schizophrenia. The aim of this study was to identify additional genetic factors (i.e., "second hits") that may contribute to schizophrenia expression. METHOD: Through an international consortium, the authors obtained DNA samples from 329 psychiatrically phenotyped subjects with 22q11.2DS. Using a high-resolution microarray platform and established methods to assess copy number variation (CNV), the authors compared the genome-wide burden of rare autosomal CNV, outside of the 22q11.2 deletion region, between two groups: a schizophrenia group and those with no psychotic disorder at age ≥25 years. The authors assessed whether genes overlapped by rare CNVs were overrepresented in functional pathways relevant to schizophrenia. RESULTS: Rare CNVs overlapping one or more protein-coding genes revealed significant between-group differences. For rare exonic duplications, six of 19 gene sets tested were enriched in the schizophrenia group; genes associated with abnormal nervous system phenotypes remained significant in a stepwise logistic regression model and showed significant interactions with 22q11.2 deletion region genes in a connectivity analysis. For rare exonic deletions, the schizophrenia group had, on average, more genes overlapped. The additional rare CNVs implicated known (e.g., GRM7, 15q13.3, 16p12.2) and novel schizophrenia risk genes and loci. CONCLUSIONS: The results suggest that additional rare CNVs overlapping genes outside of the 22q11.2 deletion region contribute to schizophrenia risk in 22q11.2DS, supporting a multigenic hypothesis for schizophrenia. The findings have implications for understanding expression of psychotic illness and herald the importance of whole-genome sequencing to appreciate the overall genomic architecture of schizophrenia.