Browsing by Author "Hestand, Matthew"

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    Deletion size analysis of 1680 22q11.2DS subjects identifies a new recombination hotspot on chromosome 22q11.2
    (2018) Guo, Tingwei; Diacou, Alexander; Nomaru, Hiroko; McDonald-McGinn, Donna M.; Hestand, Matthew; Demaerel, Wolfram; Zhang, Liangtian; Zhao, Yingjie; Ujueta, Francisco; Shan, Jidong; Montagna, Cristina; Zheng, Deyou; Crowley, Terrence B.; Kushan-Wells, Leila; Bearden, Carrie E.; Kates, Wendy R.; Gothelf, Doron; Schneider, Maude; Eliez, Stephan; Breckpot, Jeroen; Swillen, Ann; Vorstman, Jacob; Zackai, Elaine; Benavides, Felipe; Repetto, Gabriela; Emanuel, Beverly S.; Bassett, Anne S.; Vermeesch, Joris R.; Marshall, Christian R.; Morrow, Bernice E.
    Recurrent, de novo, meiotic non-allelic homologous recombination events between low copy repeats, termed LCR22s, leads to the 22q11.2 deletion syndrome (22q11.2DS; velo-cardio-facial syndrome/DiGeorge syndrome). Although most 22q11.2DS patients have a similar sized 3 million base pair (Mb), LCR22A-D deletion, some have nested LCR22A-B or LCR22A-C deletions. Our goal is to identify additional recurrent 22q11.2 deletions associated with 22q11.2DS, serving as recombination hotspots for meiotic chromosomal rearrangements. Here, using data from Affymetrix 6.0 microarrays on 1680 22q11.2DS subjects, we identified what appeared to be a nested proximal 22q11.2 deletion in 38 (2.3%) of them. Using molecular and haplotype analyses from 14 subjects and their parent(s) with available DNA, we found essentially three types of scenarios to explain this observation. In eight subjects, the proximal breakpoints occurred in a small sized 12 kb LCR distal to LCR22A, referred to LCR22Aþ, resulting in LCR22Aþ-B or LCR22Aþ-D deletions. Six of these eight subjects had a nested 22q11.2 deletion that occurred during meiosis in a parent carrying a benign 0.2 Mb duplication of the LCR22A-LCR22Aþregion with a breakpoint in LCR22Aþ. Another six had a typical de novo LCR22A-D deletion on one allele and inherited the LCR22A-Aþduplication from the other parent thus appearing on microarrays to have a nested deletion. LCR22Aþmaps to an evolutionary breakpoint between mice and humans and appears to serve as a local hotspot for chromosome rearrangements on 22q11.2.
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    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, Gabriela
    Schizophrenia 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 present

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