Browsing by Author "Sauerbeck, Laura"

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    Genome-wide association study of intracranial aneurysm identifies a new association on chromosome 7
    (Ovid Technologies Wolters Kluwer – American Heart Association, 2014-11) Foroud, Tatiana; Lai, Dongbing; Koller, Daniel; van’t Hof, Femke; Kurki, Mitja I.; Anderson, Craig S.; Brown, Robert D.; Connolly, E. Sander; Eriksson, Johan G.; Flaherty, Matthew; Fornage, Myriam; von und zuFraunberg, Mikael; Gaál, Emília I.; Laakso, Aki; Hernesniemi, Juha; Huston, John; Jääskeläinen, Juha E.; Kiemeney, Lambertus A.; Kivisaari, Riku; Kleindorfer, Dawn; Ko, Nerissa; Lehto, Hanna; Mackey, Jason; Meissner, Irene; Moomaw, Charles J.; Mosley, Thomas H.; Moskala, Marek; Niemelä, Mika; Palotie, Aarno; Pera, Joanna; Rinkel, Gabriel; Ripke, Stephan; Rouleau, Guy; Ruigrok, Ynte; Sauerbeck, Laura; Słowik, Agnieszka; Vermeulen, Sita H.; Woo, Daniel; Worrall, Bradford B.; Broderick, Joseph; Department of Medical & Molecular Genetics, IU School of Medicine
    BACKGROUND AND PURPOSE: Common variants have been identified using genome-wide association studies which contribute to intracranial aneurysms (IA) susceptibility. However, it is clear that the variants identified to date do not account for the estimated genetic contribution to disease risk. METHODS: Initial analysis was performed in a discovery sample of 2617 IA cases and 2548 controls of white ancestry. Novel chromosomal regions meeting genome-wide significance were further tested for association in 2 independent replication samples: Dutch (717 cases; 3004 controls) and Finnish (799 cases; 2317 controls). A meta-analysis was performed to combine the results from the 3 studies for key chromosomal regions of interest. RESULTS: Genome-wide evidence of association was detected in the discovery sample on chromosome 9 (CDKN2BAS; rs10733376: P<1.0×10(-11)), in a gene previously associated with IA. A novel region on chromosome 7, near HDAC9, was associated with IA (rs10230207; P=4.14×10(-8)). This association replicated in the Dutch sample (P=0.01) but failed to show association in the Finnish sample (P=0.25). Meta-analysis results of the 3 cohorts reached statistical significant (P=9.91×10(-10)). CONCLUSIONS: We detected a novel region associated with IA susceptibility that was replicated in an independent Dutch sample. This region on chromosome 7 has been previously associated with ischemic stroke and the large vessel stroke occlusive subtype (including HDAC9), suggesting a possible genetic link between this stroke subtype and IA.
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    Lessons learned from whole exome sequencing in multiplex families affected by a complex genetic disorder, intracranial aneurysm
    (PLoS, 2015-03-24) Farlow, Janice L.; Lin, Hai; Sauerbeck, Laura; Lai, Dongbing; Koller, Daniel L.; Pugh, Elizabeth; Hetrick, Kurt; Ling, Hua; Kleinloog, Rachel; van der Vlies, Peter; Deelen, Patrick; Swertz, Morris A.; Verweij, Bon H.; Regli, Luca; Rinkel, Gabriel J.E.; Ruigrok, Ynte M.; Doheny, Kimberly; Liu, Yunlong; Broderick, Joseph; Foroud, Tatiana; Department of Medical and Molecular Genetics, IU School of Medicine
    Genetic risk factors for intracranial aneurysm (IA) are not yet fully understood. Genomewide association studies have been successful at identifying common variants; however, the role of rare variation in IA susceptibility has not been fully explored. In this study, we report the use of whole exome sequencing (WES) in seven densely-affected families (45 individuals) recruited as part of the Familial Intracranial Aneurysm study. WES variants were prioritized by functional prediction, frequency, predicted pathogenicity, and segregation within families. Using these criteria, 68 variants in 68 genes were prioritized across the seven families. Of the genes that were expressed in IA tissue, one gene (TMEM132B) was differentially expressed in aneurysmal samples (n=44) as compared to control samples (n=16) (false discovery rate adjusted p-value=0.023). We demonstrate that sequencing of densely affected families permits exploration of the role of rare variants in a relatively common disease such as IA, although there are important study design considerations for applying sequencing to complex disorders. In this study, we explore methods of WES variant prioritization, including the incorporation of unaffected individuals, multipoint linkage analysis, biological pathway information, and transcriptome profiling. Further studies are needed to validate and characterize the set of variants and genes identified in this study.
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    PRIORITIZATION OF RESULTS FROM WHOLE EXOME SEQUENCING IN FAMILIAL INTRACRANIAL ANEURYSM
    (Office of the Vice Chancellor for Research, 2012-04-13) Farlow, Janice L.; Lin, Hai; Hetrick, Kurt; Ling, Hua; Lai, Dongbing; Sauerbeck, Laura; Woo, Daniel; Langefeld, Carl; Brown, Robert; Pugh, Elizabeth; Doheny, Kimberly; Liu, Yunlong; Foroud, Tatiana; Broderick, Joseph; Foroud, Tatiana
    Whole exome sequencing (WES) is an innovative approach to identifying rare variants associated with disease; however, reducing the large number of variants to a useful set of candidate genes is challenging. We developed a ranking system utilizing data from a previous genome-wide linkage analysis and various bioinformatics databases to prioritize the results of WES from families having multiple members with intracranial aneurysms. WES was performed in 35 affected individuals and 10 unaffected individ-uals across 7 families. All samples were genotyped (Illumina® OmniExpress) and sequenced (Agilent© SureSelect™ 50Mb Human All Exon Kit). Linkage analysis (Illumina 6K) was previously performed using autosomal domi-nant/recessive modes of inheritance. Application of quality filters resulted in 91,659 single nucleotide variants (SNVs). Nonsynonymous SNVs within an exon having an allele frequency of <3% were retained. Further filtering was performed based on Mendelian in-heritance (autosomal dominant or recessive). A ranking system prioritized retained variants based on the inheritance pattern specific to each family, occurrence in multiple families, relation to pathways and genes of interest, degree of penetrance, presence within a linkage peak, and whether the re-sultant proteins were predicted to be deleterious. Out of a 9-point score, 292 variants in 190 genes received scores of at least 5. Of these, 14 variants in 10 genes met the majority of prioritization criteria by achieving scores of over 7. While several WES studies have been successful at identifying genes im-portant to rare diseases, few have examined how to produce a list of candi-date genes contributing to a complex disease from WES data. We show that a ranking system that combines WES with bioinformatics resources and link-age data is a powerful approach to prioritize candidate genes for a complex disease like familial intracranial aneurysms. Subsequent studies are required to validate the utility of this approach.
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    Screening for brain aneurysm in the Familial Intracranial Aneurysm study: frequency and predictors of lesion detection
    (Journal of Neurosurgery Publishing Group (JNSPG), 2008-06) Brown, Robert D., Jr.; Huston, John, III; Hornung, Richard; Foroud, Tatiana; Kallmes, David F.; Kleindorfer, Dawn; Meissner, Irene; Woo, Daniel; Sauerbeck, Laura; Broderick, Joseph; Department of Medical & Molecular Genetics, School of Medicine,
    Object Approximately 20% of patients with an intracranial saccular aneurysm report a family history of intracranial aneurysm (IA) or subarachnoid hemorrhage. A better understanding of predictors of aneurysm detection in familial IA may allow more targeted aneurysm screening strategies. Methods The Familial Intracranial Aneurysm (FIA) study is a multicenter study, in which the primary objective is to define the susceptibility genes related to the formation of IA. First-degree relatives (FDRs) of those affected with IA are offered screening with magnetic resonance (MR) angiography if they were previously unaffected, are ≥ 30 years of age, and have a history of smoking and/or hypertension. Independent predictors of aneurysm detection on MR angiography were determined using the generalized estimating equation version of logistic regression. Results Among the first 303 patients screened with MR angiography, 58 (19.1%) had at least 1 IA, including 24% of women and 11.7% of men. Ten (17.2%) of 58 affected patients had multiple aneurysms. Independent predictors of aneurysm detection included female sex (odds ratio [OR] 2.46, p = 0.001), pack-years of cigarette smoking (OR 3.24 for 20 pack-years of cigarette smoking compared with never having smoked, p < 0.001), and duration of hypertension (OR 1.26 comparing those with 10 years of hypertension to those with no hypertension, p = 0.006). Conclusions In the FIA study, among the affected patients’ FDRs who are > 30 years of age, those who are women or who have a history of smoking or hypertension are at increased risk of suffering an IA and should be strongly considered for screening.