TY - JOUR
T1 - Whole-exome sequencing of individuals from an isolated population implicates rare risk variants in bipolar disorder
AU - Lescai, F
AU - Als, T D
AU - Li, Q
AU - Nyegaard, M
AU - Andorsdottir, G
AU - Biskopstø, M
AU - Hedemand, A
AU - Fiorentino, A
AU - O'Brien, N
AU - Jarram, A
AU - Liang, J
AU - Grove, J
AU - Pallesen, J
AU - Eickhardt, E
AU - Mattheisen, M
AU - Bolund, L
AU - Demontis, D
AU - Wang, A G
AU - McQuillin, A
AU - Mors, O
AU - Wang, J
AU - Børglum, A D
PY - 2017
Y1 - 2017
N2 - Bipolar disorder affects about 1% of the world's population, and its estimated heritability is about 75%. Only few whole genome or whole-exome sequencing studies in bipolar disorder have been reported, and no rare coding variants have yet been robustly identified. The use of isolated populations might help finding variants with a recent origin, more likely to have drifted to higher frequency by chance. Following this approach, we investigated 28 bipolar cases and 214 controls from the Faroe Islands by whole exome sequencing, and the results were followed-up in a British sample of 2025 cases and 1358 controls. Seventeen variants in 16 genes in the single-variant analysis, and 3 genes in the gene-based statistics surpassed exome-wide significance in the discovery phase. The discovery findings were supported by enrichment analysis of common variants from genome-wide association studies (GWAS) data and interrogation of protein-protein interaction networks. The replication in the British sample confirmed the association with NOS1 (missense variant rs79487279) and NCL (gene-based test). A number of variants from the discovery set were not present in the replication sample, including a novel PITPNM2 missense variant, which is located in a highly significant schizophrenia GWAS locus. Likewise, PIK3C2A identified in the gene-based analysis is located in a combined bipolar and schizophrenia GWAS locus. Our results show support both for existing findings in the literature, as well as for new risk genes, and identify rare variants that might provide additional information on the underlying biology of bipolar disorder.
AB - Bipolar disorder affects about 1% of the world's population, and its estimated heritability is about 75%. Only few whole genome or whole-exome sequencing studies in bipolar disorder have been reported, and no rare coding variants have yet been robustly identified. The use of isolated populations might help finding variants with a recent origin, more likely to have drifted to higher frequency by chance. Following this approach, we investigated 28 bipolar cases and 214 controls from the Faroe Islands by whole exome sequencing, and the results were followed-up in a British sample of 2025 cases and 1358 controls. Seventeen variants in 16 genes in the single-variant analysis, and 3 genes in the gene-based statistics surpassed exome-wide significance in the discovery phase. The discovery findings were supported by enrichment analysis of common variants from genome-wide association studies (GWAS) data and interrogation of protein-protein interaction networks. The replication in the British sample confirmed the association with NOS1 (missense variant rs79487279) and NCL (gene-based test). A number of variants from the discovery set were not present in the replication sample, including a novel PITPNM2 missense variant, which is located in a highly significant schizophrenia GWAS locus. Likewise, PIK3C2A identified in the gene-based analysis is located in a combined bipolar and schizophrenia GWAS locus. Our results show support both for existing findings in the literature, as well as for new risk genes, and identify rare variants that might provide additional information on the underlying biology of bipolar disorder.
KW - Bipolar Disorder/genetics
KW - Calcium-Binding Proteins/genetics
KW - Case-Control Studies
KW - Denmark
KW - Gene Regulatory Networks
KW - Genetic Predisposition to Disease
KW - Humans
KW - Membrane Proteins/genetics
KW - Mutation, Missense
KW - Nitric Oxide Synthase Type I/genetics
KW - Phosphatidylinositol 3-Kinases/genetics
KW - Phosphoproteins/genetics
KW - Polymorphism, Genetic
KW - RNA-Binding Proteins/genetics
KW - Sequence Analysis, DNA
KW - United Kingdom
U2 - 10.1038/tp.2017.3
DO - 10.1038/tp.2017.3
M3 - Journal article
C2 - 28195573
SN - 2158-3188
VL - 7
JO - Translational Psychiatry
JF - Translational Psychiatry
M1 - e1034
ER -