A locus for bipolar affective disorder on chromosome 4p

Blackwood, Douglas; Morris, Stewart W.; McLean, Alan W.; Whitton, Claire; Thomson, Marian; Walker, M.; Woodburn, Kirstie; Sharp, C. M.; Wright, Alan F.; Shibasaki, Y.; Clair, David Malcolm St; Porteous, David J.; Muir, Walter

doi:10.1038/ng0496-427

Cited by 262 publications

(220 citation statements)

References 27 publications

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“…38 Usher syndrome can cause central nervous system structural changes 39 and psychosis, 40 and there is one report of increased incidence of bipolar disorder among adults with prelingual-onset nonsyndromic deafness, 41 but it is not known if any of those patients carried the 'whirler' mutation. Finally, SORCS2 maps to a region on chromosome 4p that has been widely linked to bipolar disorder 42 (Supplementary References). SORCS2 encodes a VPS10 domain-containing receptor prominently expressed in the developing brain.…”

Section: Ae Baum Et Almentioning

confidence: 99%

A genome-wide association study implicates diacylglycerol kinase eta (DGKH) and several other genes in the etiology of bipolar disorder

et al. 2007

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The genetic basis of bipolar disorder has long been thought to be complex, with the potential involvement of multiple genes, but methods to analyze populations with respect to this complexity have only recently become available. We have carried out a genome-wide association study of bipolar disorder by genotyping over 550 000 single-nucleotide polymorphisms (SNPs) in two independent case-control samples of European origin. The initial association screen was performed using pooled DNA, and selected SNPs were confirmed by individual genotyping. While DNA pooling reduces power to detect genetic associations, there is a substantial cost saving and gain in efficiency. A total of 88 SNPs, representing 80 different genes, met the prior criteria for replication in both samples. Effect sizes were modest: no single SNP of large effect was detected. Of 37 SNPs selected for individual genotyping, the strongest association signal was detected at a marker within the first intron of diacylglycerol kinase eta (DGKH; P = 1.5 Â 10 À8 , experiment-wide P < 0.01, OR = 1.59). This gene encodes DGKH, a key protein in the lithium-sensitive phosphatidyl inositol pathway. This first genome-wide association study of bipolar disorder shows that several genes, each of modest effect, reproducibly influence disease risk. Bipolar disorder may be a polygenic disease.

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Section: Ae Baum Et Almentioning

confidence: 99%

A genome-wide association study implicates diacylglycerol kinase eta (DGKH) and several other genes in the etiology of bipolar disorder

et al. 2007

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“…Among these regions we retained the 4p16 locus since significant linkage with BD was found in Scottish, Danish and American pedigrees. [2][3][4][5] A recent study on Faroese population confirmed the link between this locus and BD and schizophrenia. 6 The 4p16 region encodes several interesting candidate genes such as ADRA2C (a-adrenergic receptor 2C), WFS1 (wolframin; heterozygous carriers display an estimated 26-fold increased incidence of psychiatric illness 7 ) or DRD5 (dopamine D5 receptor) genes.…”

Section: Introductionmentioning

confidence: 99%

PP2A-Bγ subunit and KCNQ2 K+ channels in bipolar disorder

Borsotto

Cavarec²,

Bouillot³

et al. 2006

Pharmacogenomics J

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Many bipolar affective disorder (BD) susceptibility loci have been identified but the molecular mechanisms responsible for the disease remain to be elucidated. In the locus 4p16, several candidate genes were identified but none of them was definitively shown to be associated with BD. In this region, the PPP2R2C gene encodes the Bg-regulatory subunit of the protein phosphatase 2A (PP2A-Bg). First, we identified, in two different populations, single nucleotide polymorphisms and risk haplotypes for this gene that are associated to BD. Then, we used the Bg subunit as bait to screen a human brain cDNA library with the yeast two-hybrid technique. This led us to two new splice variants of KCNQ2 channels and to the KCNQ2 channel itself. This unusual K þ channel has particularly interesting functional properties and belongs to a channel family that is already known to be implicated in several other monogenic diseases. In one of the BD populations, we also found a genetic association between the KCNQ2 gene and BD. We show that KCNQ2 splice variants differ from native channels by their shortened C-terminal sequences and are unique as they are active and exert a dominant-negative effect on KCNQ2 wild-type (wt) channel activity. We also show that the PP2A-Bg subunit significantly increases the current generated by KCNQ2wt, a channel normally inhibited by phosphorylation. The kinase glycogen synthase kinase 3 beta (GSK3b) is considered as an interesting target of lithium, the classical drug used in BD. GSK3b phosphorylates the KCNQ2 channel and this phosphorylation is decreased by Li þ .

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“…In particular, findings in 4p, 4q, 8q, 10p, 12q24, 13q, 18p, 18q, 21q, and 22q have been supported by more than one study. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] However, these studies have not identified any specific genes, and a recent metaanalysis of available genome scans showed no regions with a conclusive evidence of linkage. 20 The relatively slow progress of gene-mapping efforts is often explained by the 'complex' nature of the illness and of the genotype-phenotype relation.…”

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confidence: 99%

The phenotypes of bipolar disorder: relevance for genetic investigations

2005

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The search for susceptibility genes for bipolar disorder (BD) depends on appropriate definitions of the phenotype. In this paper, we review data on diagnosis and clinical features of BD that could be used in genetic studies to better characterize patients or to define homogeneous subgroups. Clinical symptoms, long-term course, comorbid conditions, and response to prophylactic treatment may define groups associated with more or less specific loci. One such group is characterized by symptoms of psychosis and linkage to 13q and 22q. A second group includes mainly bipolar II patients with comorbid panic disorder, rapid mood switching, and evidence of chromosome 18 linkage. A third group comprises typical BD with an episodic course and favourable response to lithium prophylaxis. Reproducibility of cognitive deficits across studies raises the possibility of using cognitive profiles as endophenotypes of BD, with deficits in verbal explicit memory and executive function commonly reported. Brain imaging provides a more ambiguous data set consistent with heterogeneity of the illness. Keywords: bipolar disorder; genetics; endophenotype; neurocognitive function; brain imaging Bipolar disorder (BD) has a genetic basis with heritability of at least 80%. 1 A number of studies have attempted to map the susceptibility loci giving evidence of linkage in multiple genomic regions. In particular, findings in 4p, 4q, 8q, 10p, 12q24, 13q, 18p, 18q, 21q, and 22q have been supported by more than one study. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] However, these studies have not identified any specific genes, and a recent metaanalysis of available genome scans showed no regions with a conclusive evidence of linkage. 20 The relatively slow progress of gene-mapping efforts is often explained by the 'complex' nature of the illness and of the genotype-phenotype relation. The complexity most likely includes heterogeneity, interactions of multiple loci, incomplete penetrance, as well as phenotypes resulting from environmental effects-either alone or in interaction with the genetic predisposition. The goal of psychiatric genetic research is identification of (heritable) variations in DNA sequence or function that influence behaviour or give rise to mental illness. By definition, in complex (multifactorial) traits, this link is not unique and specific. That is, a particular change in gene sequence does not necessarily lead to a specific behaviour, and similar behaviours (symptoms) may be due to distinct (sets of) genes. Moreover, we must consider the possibility that the path between the genotype and behaviour is not unidirectional. Emerging examples point not only to general effects of environment, for instance stress, on behaviour, but also to specific behaviours influencing gene function that can be transmitted onto the next generation. 21 No single method is considered clearly superior in identifying susceptibility genes for complex traits such as BD. Most researchers agree that a combination of strategies is most lik...

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A locus for bipolar affective disorder on chromosome 4p

Cited by 262 publications

References 27 publications

A genome-wide association study implicates diacylglycerol kinase eta (DGKH) and several other genes in the etiology of bipolar disorder

A genome-wide association study implicates diacylglycerol kinase eta (DGKH) and several other genes in the etiology of bipolar disorder

PP2A-Bγ subunit and KCNQ2 K+ channels in bipolar disorder

The phenotypes of bipolar disorder: relevance for genetic investigations

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