- Email: [email protected]
GENOME-WIDE DNA METHYLATION SIGNATURES OF AGGRESSION RISK IN CHILDREN
Abstracts
Background: Mitochondrial DNA (mtDNA) haplogroups (hgs) are evolutionarily conserved sets of mtDNA SNPs. Associations of hgs with geographical origin, disease and physiological characteristics have been reported, but have frequently not been reproducible. We assessed, using 418 mtDNA SNPs on the PsychChip (Illumina), the spatio-temporal distribution of mtDNA hgs in DNA isolated from geographically un-biased dried blood spots (DBS), collected from 1981 to 2005 through the Danish National Neonatal Screening program. Methods: As part of the iPSYCH (www.iPSYCH.au.dk) recruitment protocol, 24,651 singletons (47.1% female), born between May 1 1981 and Dec 31 2005 were selected at random from the Danish Central Person Registry. The Samples were extracted from the Danish National Biobank and Genotyped at the Broad Institute as part of iPSYCH and PGC. Haplotyping of mtDNA was performed using the defining SNPs reported in www.phylotree.org. First the affiliation to macro-hg i.e. L0 – L6, M, N, R, and then to hgs – units more distal in the cladogram was established. Ancestry estimation was done using ADMIXTURE 1.3.052. Briefly, a reference population consisting of Human Genome Diversity Project (HGDP) (http://www.hagsc.org/hgdp/) genotyping SNP data set, supplemented with representative samples of danes (716 individuals) and greenlanders (592 individuals) available at SSI, was used. Results: The hg distribution was typically Northern European, and hgs were highly variable based on medianjoining analysis, suggesting multiple founder events. Considerable heterogeneity and variation in autosomal genogeographic affinity (ancestry) was observed. Thus, individuals with hg H exhibited 95%, and U hgs 38.2% - 92.5%, Danish ancestry. Significant clines between geographical regions and rural and metropolitan populations were found. Over 25 years, macro-hg L increased from 0.2% to 1.2% (p = 1.1nE-10), and M from 1% to 2.4% (p= 3.7nE-8). Hg U increased among the R macro-hg from 14.1% to 16.5% (p = 1.9nE-3). Geno-geographic affinity, geographical skewedness, and sub-hg distribution suggested that the L, M and U increases are due to immigration. Discussion: This study shows that the distribution of mtDNA hgs in Denmark is highly dynamic and complex. It comprises 1.6% of the Danish population over a 25-year period, and is by far the largest ever performed of the distribution of mtDNA hgs in any country. The method of collecting stored DBS from the PKU biobank, where the coverage is 99%, enabled us to survey a true population based sample, where the time and place of birth was known from national electronic registries. This is in contrast to most other population genetic studies of adults sampled in a specific bias-prone context, e.g. hospitalized patients or localized samplings. The mtDNA haplotyping was based on array data with only 418 mtDNA SNPs and as a consequence not all sub-hgs could be called. The stringent adherence to specific SNPs left a number of persons, normally in the order of 1–2%, not haplotypable. An advantage of only using a limited set of markers is that confounding due to private variants is avoided.
S997
Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.euroneuro.2017.08.384
M78. GENES IMPLICATED IN NEURODEVELOPMENT ARE ENRICHED FOR FOXP2 BINDING SITES ASSOCIATED WITH LANGUAGE ABILITY n
Tanner Koomar , Bruce Tomblin, Jacob Michaelson University of Iowa
Background: Specific Language Impairment (SLI) is a neurodevelopmental condition which causes linguistic deficits in children with otherwise normal development. SLI is demonstrably heritable (h2 0.6) and relatively common (occurring in 7% of the population). Linkage, GWAS, and twin studies of SLI have produced mixed results with inconsistent replication, necessitating the integration of other forms of molecular data related to language ability into its study. The transcription factor FOXP2 is robustly associated with language ability, with perturbations to the coding region of the gene resulting in severe language deficits. However, such coding changes in FOXP2 are exceedingly rare. Variation in FOXP2's thousands of DNA binding sites is plentiful, on the other hand, making them attractive targets for interrogation in a common condition like SLI. Methods: Genetic variants overlapping FOXP2 ChIP peak sites were extracted from the whole genome sequences of a cohort of 280 children (140 SLI and 140 control), and ranked based on association with overall language ability. Variation in the FOXP2 locus was also tested for association with language ability. Results: Genes co-expressed with FOXP2 in the developing human brain and implicated in neurodevelopment were enriched for high-ranking FOXP2 binding sites. Despite these intriguing results, this variation – and that in the FOXP2 locus itself – was only able to explain a fraction of differences in total language ability. Discussion: These results show the promise of integrating molecular data into genetic analysis of SLI, while demonstrating the inability of FOXP2 to fully explain the preponderance of variability in human language ability. Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.euroneuro.2017.08.385
M79. GENOME-WIDE DNA METHYLATION SIGNATURES OF AGGRESSION RISK IN CHILDREN n
Janitza Montalvo-Ortiz ,1, James Hudziak2, Hannah Holbrook2, Kerry O'Loughlin2, Joel Gelernter1, Joan Kaufman3 1
Yale University School of Medicine
S998 2 3
Abstracts
University of Vermont Kennedy Krieger Institute, Johns Hopkins University
Background: Child abuse is a highly prevalent public health problem and a risk factor for numerous psychopathological disorders. Early physical abuse and neglect have been associated with an increased risk of childhood conduct disorders. However, not all children exposed to abuse develop aggression later in life, suggesting interplay between genetic and environmental factors in the predisposition to aggression. Methods: This study investigated genome-wide DNA methylation changes associated with aggressive behavior in children. A total of 105 9–15 years old children of European ancestry were included in the study (56% female, 12 7 1.8 mean of age). The Illumina Infinium 450 K Methylation BeadChip array was used to conduct the methylation study using the genomic DNA extracted from saliva samples. Aggression was evaluated using the Child Behavior Checklist (CBCL) Scores ranged from 50–87 (mean: 57 7 10.5), with 39% of the sample meeting the clinical cutoff (r 63). We conducted a linear mixed effects model to examine the main effect of trauma, main effect of DNA methylation and an interaction term, and adjusted for age, sex, cell composition, and 10 principal components (PCs) estimated using Barfield et al. method. Significance was set to 5.0 10-7 to correct for multiple comparisons. Results: A total of eight methylation sites were genomewide significant (GWS) for the DNA methylation term after adjusting for age, sex, cell type composition and 10 PCs. From these sites, cg18438793 (p = 2.58 10-7) located within the hippocalcin like 4 (HPCAL4) gene is of importance due to its role in neuronal development and calcium signaling and brain-specific gene expression. Further, expression of this gene is induced after fear conditioning in the lateral amygdala of mice. Additional sites (p value range: 10-10 – 10-7) are involved in axon guidance, myelination and transcriptional regulation. Discussion: This study increases our understanding of the epigenetic changes associated with aggression in children. By identifying predictors of aggression in early life, this study may provide novel tools to improve treatment and preventive interventions for aggression risk in children.
Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.euroneuro.2017.08.386
M80. METABOLIC ABNORMALITIES RELATED TO TREATMENT WITH SELECTIVE SEROTONIN REUPTAKE INHIBITORS IN PATIENTS WITH SCHIZOPHRENIA OR BIPOLAR DISORDER: A GENOME WIDE ASSOCIATION STUDY n
Katrine Fjukstad ,1, Lavinia Athanasiu2, Ingrid Dieset2, Nils Steen2, Srdjan Djurovic2, Olav Spigset3, Ole Andreassen2 1
Nord-Trøndelag Hospital Trust NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo
2
3
Norwegian University of Science and Technology, St. Olav University Hospital
Background: Patients’ tolerability and experienced efficacy of psychopharmacological drugs such as Selective Serotonin Reuptake Inhibitors (SSRIs) are influenced by both environmental and genetic factors. SSRIs are sometimes used as add-on therapy in schizophrenia and bipolar disorder. Association between use of SSRIs and metabolic abnormalities has been shown, but little is known about the genetic associations in this context. Our aim is to study genetic variations associated with individual differences in SSRI-induced metabolic side effects. Methods: We conducted a genome-wide association study to identify genetic variants affecting susceptibility to SSRIinduced metabolic abnormalities by using data from the Norwegian Thematically Organized Psychosis study. Patients (n = 1120) suffering from schizophrenia (n = 719) or bipolar disorder (n= 401) were included. SSRI exposure was expressed in dosages or serum concentrations of SSRIs (n= 237). Metabolic outcome variables were: Levels of total cholesterol, low and high density lipoprotein (LDL and HDL) cholesterol, triglycerides, glucose and Body Mass Index (BMI). Single nucleotide polymorphisms (SNP) and use of SSRIs were tested for associations to outcome variables. To account for the effect of age, gender and co-medication with olanzapine, quetiapine or clozapine, these were included as covariates in the analysis. Results: In preliminary analysis, we identified 31 regions associated with SSRI-induced metabolic abnormalities in outcome variables total cholesterol level, HDL- and LDL cholesterol levels and triglycerides (significance threshold: P o 10-8). For triglycerides, our strongest association was for marker rs13428203 (P = 3.11E-17) located upstream of the gene SNORD95 on chromosome 2 followed by 4 markers (Po 2.16E-14) located in intergenic regions on chromosome 2, and finally (P= 1.30E-09) and rs17200837 (P= 1.33E-09) located in PRRC2A on chromosome 6. Additionally, 11 other markers were significantly associated with triglycerides (Po 8.32E-09). One marker, rs7412, located on chromosome 19 in APOE that encodes apolipoprotein E, was significantly associated with both total cholesterol and LDL-cholesterol levels. Moreover, we observed 15 markers that were significantly associated with HDL cholesterol levels when accounting for SSRI use. The strongest signal was for rs4893537 in ACSL4 on chromosome x (P= 3.05E-12), which has a function in lipid biosynthesis and fatty acid degradation. Discussion: The present findings indicate that SSRIinduced metabolic abnormalities are potentially affected by common genetic variation. Several markers were associated with triglyceride levels, with strongest signal seen for marker rs13428203, and for several markers in PRRC2A gene, previously associated with age-at-onset of insulindependent diabetes mellitus, as well as a possible involvement in the inflammatory process of pancreatic beta-cell destruction during development of insulin-dependent diabetes mellitus. Further, markers in APOE were associated with both total cholesterol-and LDL cholesterol levels. In addition, several variants in ACSL4 were associated with HDL cholesterol. Our findings warrant further investigation
Background: Mitochondrial DNA (mtDNA) haplogroups (hgs) are evolutionarily conserved sets of mtDNA SNPs. Associations of hgs with geographical origin, disease and physiological characteristics have been reported, but have frequently not been reproducible. We assessed, using 418 mtDNA SNPs on the PsychChip (Illumina), the spatio-temporal distribution of mtDNA hgs in DNA isolated from geographically un-biased dried blood spots (DBS), collected from 1981 to 2005 through the Danish National Neonatal Screening program. Methods: As part of the iPSYCH (www.iPSYCH.au.dk) recruitment protocol, 24,651 singletons (47.1% female), born between May 1 1981 and Dec 31 2005 were selected at random from the Danish Central Person Registry. The Samples were extracted from the Danish National Biobank and Genotyped at the Broad Institute as part of iPSYCH and PGC. Haplotyping of mtDNA was performed using the defining SNPs reported in www.phylotree.org. First the affiliation to macro-hg i.e. L0 – L6, M, N, R, and then to hgs – units more distal in the cladogram was established. Ancestry estimation was done using ADMIXTURE 1.3.052. Briefly, a reference population consisting of Human Genome Diversity Project (HGDP) (http://www.hagsc.org/hgdp/) genotyping SNP data set, supplemented with representative samples of danes (716 individuals) and greenlanders (592 individuals) available at SSI, was used. Results: The hg distribution was typically Northern European, and hgs were highly variable based on medianjoining analysis, suggesting multiple founder events. Considerable heterogeneity and variation in autosomal genogeographic affinity (ancestry) was observed. Thus, individuals with hg H exhibited 95%, and U hgs 38.2% - 92.5%, Danish ancestry. Significant clines between geographical regions and rural and metropolitan populations were found. Over 25 years, macro-hg L increased from 0.2% to 1.2% (p = 1.1nE-10), and M from 1% to 2.4% (p= 3.7nE-8). Hg U increased among the R macro-hg from 14.1% to 16.5% (p = 1.9nE-3). Geno-geographic affinity, geographical skewedness, and sub-hg distribution suggested that the L, M and U increases are due to immigration. Discussion: This study shows that the distribution of mtDNA hgs in Denmark is highly dynamic and complex. It comprises 1.6% of the Danish population over a 25-year period, and is by far the largest ever performed of the distribution of mtDNA hgs in any country. The method of collecting stored DBS from the PKU biobank, where the coverage is 99%, enabled us to survey a true population based sample, where the time and place of birth was known from national electronic registries. This is in contrast to most other population genetic studies of adults sampled in a specific bias-prone context, e.g. hospitalized patients or localized samplings. The mtDNA haplotyping was based on array data with only 418 mtDNA SNPs and as a consequence not all sub-hgs could be called. The stringent adherence to specific SNPs left a number of persons, normally in the order of 1–2%, not haplotypable. An advantage of only using a limited set of markers is that confounding due to private variants is avoided.
S997
Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.euroneuro.2017.08.384
M78. GENES IMPLICATED IN NEURODEVELOPMENT ARE ENRICHED FOR FOXP2 BINDING SITES ASSOCIATED WITH LANGUAGE ABILITY n
Tanner Koomar , Bruce Tomblin, Jacob Michaelson University of Iowa
Background: Specific Language Impairment (SLI) is a neurodevelopmental condition which causes linguistic deficits in children with otherwise normal development. SLI is demonstrably heritable (h2 0.6) and relatively common (occurring in 7% of the population). Linkage, GWAS, and twin studies of SLI have produced mixed results with inconsistent replication, necessitating the integration of other forms of molecular data related to language ability into its study. The transcription factor FOXP2 is robustly associated with language ability, with perturbations to the coding region of the gene resulting in severe language deficits. However, such coding changes in FOXP2 are exceedingly rare. Variation in FOXP2's thousands of DNA binding sites is plentiful, on the other hand, making them attractive targets for interrogation in a common condition like SLI. Methods: Genetic variants overlapping FOXP2 ChIP peak sites were extracted from the whole genome sequences of a cohort of 280 children (140 SLI and 140 control), and ranked based on association with overall language ability. Variation in the FOXP2 locus was also tested for association with language ability. Results: Genes co-expressed with FOXP2 in the developing human brain and implicated in neurodevelopment were enriched for high-ranking FOXP2 binding sites. Despite these intriguing results, this variation – and that in the FOXP2 locus itself – was only able to explain a fraction of differences in total language ability. Discussion: These results show the promise of integrating molecular data into genetic analysis of SLI, while demonstrating the inability of FOXP2 to fully explain the preponderance of variability in human language ability. Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.euroneuro.2017.08.385
M79. GENOME-WIDE DNA METHYLATION SIGNATURES OF AGGRESSION RISK IN CHILDREN n
Janitza Montalvo-Ortiz ,1, James Hudziak2, Hannah Holbrook2, Kerry O'Loughlin2, Joel Gelernter1, Joan Kaufman3 1
Yale University School of Medicine
S998 2 3
Abstracts
University of Vermont Kennedy Krieger Institute, Johns Hopkins University
Background: Child abuse is a highly prevalent public health problem and a risk factor for numerous psychopathological disorders. Early physical abuse and neglect have been associated with an increased risk of childhood conduct disorders. However, not all children exposed to abuse develop aggression later in life, suggesting interplay between genetic and environmental factors in the predisposition to aggression. Methods: This study investigated genome-wide DNA methylation changes associated with aggressive behavior in children. A total of 105 9–15 years old children of European ancestry were included in the study (56% female, 12 7 1.8 mean of age). The Illumina Infinium 450 K Methylation BeadChip array was used to conduct the methylation study using the genomic DNA extracted from saliva samples. Aggression was evaluated using the Child Behavior Checklist (CBCL) Scores ranged from 50–87 (mean: 57 7 10.5), with 39% of the sample meeting the clinical cutoff (r 63). We conducted a linear mixed effects model to examine the main effect of trauma, main effect of DNA methylation and an interaction term, and adjusted for age, sex, cell composition, and 10 principal components (PCs) estimated using Barfield et al. method. Significance was set to 5.0 10-7 to correct for multiple comparisons. Results: A total of eight methylation sites were genomewide significant (GWS) for the DNA methylation term after adjusting for age, sex, cell type composition and 10 PCs. From these sites, cg18438793 (p = 2.58 10-7) located within the hippocalcin like 4 (HPCAL4) gene is of importance due to its role in neuronal development and calcium signaling and brain-specific gene expression. Further, expression of this gene is induced after fear conditioning in the lateral amygdala of mice. Additional sites (p value range: 10-10 – 10-7) are involved in axon guidance, myelination and transcriptional regulation. Discussion: This study increases our understanding of the epigenetic changes associated with aggression in children. By identifying predictors of aggression in early life, this study may provide novel tools to improve treatment and preventive interventions for aggression risk in children.
Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.euroneuro.2017.08.386
M80. METABOLIC ABNORMALITIES RELATED TO TREATMENT WITH SELECTIVE SEROTONIN REUPTAKE INHIBITORS IN PATIENTS WITH SCHIZOPHRENIA OR BIPOLAR DISORDER: A GENOME WIDE ASSOCIATION STUDY n
Katrine Fjukstad ,1, Lavinia Athanasiu2, Ingrid Dieset2, Nils Steen2, Srdjan Djurovic2, Olav Spigset3, Ole Andreassen2 1
Nord-Trøndelag Hospital Trust NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo
2
3
Norwegian University of Science and Technology, St. Olav University Hospital
Background: Patients’ tolerability and experienced efficacy of psychopharmacological drugs such as Selective Serotonin Reuptake Inhibitors (SSRIs) are influenced by both environmental and genetic factors. SSRIs are sometimes used as add-on therapy in schizophrenia and bipolar disorder. Association between use of SSRIs and metabolic abnormalities has been shown, but little is known about the genetic associations in this context. Our aim is to study genetic variations associated with individual differences in SSRI-induced metabolic side effects. Methods: We conducted a genome-wide association study to identify genetic variants affecting susceptibility to SSRIinduced metabolic abnormalities by using data from the Norwegian Thematically Organized Psychosis study. Patients (n = 1120) suffering from schizophrenia (n = 719) or bipolar disorder (n= 401) were included. SSRI exposure was expressed in dosages or serum concentrations of SSRIs (n= 237). Metabolic outcome variables were: Levels of total cholesterol, low and high density lipoprotein (LDL and HDL) cholesterol, triglycerides, glucose and Body Mass Index (BMI). Single nucleotide polymorphisms (SNP) and use of SSRIs were tested for associations to outcome variables. To account for the effect of age, gender and co-medication with olanzapine, quetiapine or clozapine, these were included as covariates in the analysis. Results: In preliminary analysis, we identified 31 regions associated with SSRI-induced metabolic abnormalities in outcome variables total cholesterol level, HDL- and LDL cholesterol levels and triglycerides (significance threshold: P o 10-8). For triglycerides, our strongest association was for marker rs13428203 (P = 3.11E-17) located upstream of the gene SNORD95 on chromosome 2 followed by 4 markers (Po 2.16E-14) located in intergenic regions on chromosome 2, and finally (P= 1.30E-09) and rs17200837 (P= 1.33E-09) located in PRRC2A on chromosome 6. Additionally, 11 other markers were significantly associated with triglycerides (Po 8.32E-09). One marker, rs7412, located on chromosome 19 in APOE that encodes apolipoprotein E, was significantly associated with both total cholesterol and LDL-cholesterol levels. Moreover, we observed 15 markers that were significantly associated with HDL cholesterol levels when accounting for SSRI use. The strongest signal was for rs4893537 in ACSL4 on chromosome x (P= 3.05E-12), which has a function in lipid biosynthesis and fatty acid degradation. Discussion: The present findings indicate that SSRIinduced metabolic abnormalities are potentially affected by common genetic variation. Several markers were associated with triglyceride levels, with strongest signal seen for marker rs13428203, and for several markers in PRRC2A gene, previously associated with age-at-onset of insulindependent diabetes mellitus, as well as a possible involvement in the inflammatory process of pancreatic beta-cell destruction during development of insulin-dependent diabetes mellitus. Further, markers in APOE were associated with both total cholesterol-and LDL cholesterol levels. In addition, several variants in ACSL4 were associated with HDL cholesterol. Our findings warrant further investigation