Rare disruptive variants in the DISC1 Interactome and Regulome: association with cognitive ability and schizophrenia.

Schizophrenia (SCZ), bipolar disorder (BD) and recurrent major depressive disorder (rMDD) are common psychiatric illnesses. All have been associated with lower cognitive ability, and show evidence of genetic overlap and substantial evidence of pleiotropy with cognitive function and neuroticism. Disrupted in schizophrenia 1 (DISC1) protein directly interacts with a large set of proteins (DISC1 Interactome) that are involved in brain development and signaling. Modulation of DISC1 expression alters the expression of a circumscribed set of genes (DISC1 Regulome) that are also implicated in brain biology and disorder. Here we report targeted sequencing of 59 DISC1 Interactome genes and 154 Regulome genes in 654 psychiatric patients and 889 cognitively-phenotyped control subjects, on whom we previously reported evidence for trait association from complete sequencing of the DISC1 locus. Burden analyses of rare and singleton variants predicted to be damaging were performed for psychiatric disorders, cognitive variables and personality traits. The DISC1 Interactome and Regulome showed differential association across the phenotypes tested. After family-wise error correction across all traits (FWERacross), an increased burden of singleton disruptive variants in the Regulome was associated with SCZ (FWERacross P=0.0339). The burden of singleton disruptive variants in the DISC1 Interactome was associated with low cognitive ability at age 11 (FWERacross P=0.0043). These results identify altered regulation of schizophrenia candidate genes by DISC1 and its core Interactome as an alternate pathway for schizophrenia risk, consistent with the emerging effects of rare copy number variants associated with intellectual disability.

Do regional brain volumes and major depressive disorder share genetic architecture? A study of Generation Scotland (n=19 762), UK Biobank (n=24 048) and the English Longitudinal Study of Ageing (n=5766).

Major depressive disorder (MDD) is a heritable and highly debilitating condition. It is commonly associated with subcortical volumetric abnormalities, the most replicated of these being reduced hippocampal volume. Using the most recent published data from Enhancing Neuroimaging Genetics through Meta-analysis (ENIGMA) consortium's genome-wide association study of regional brain volume, we sought to test whether there is shared genetic architecture between seven subcortical brain volumes and intracranial volume (ICV) and MDD. We explored this using linkage disequilibrium score regression, polygenic risk scoring (PRS) techniques, Mendelian randomisation (MR) analysis and BUHMBOX. Utilising summary statistics from ENIGMA and Psychiatric Genomics Consortium, we demonstrated that hippocampal volume was positively genetically correlated with MDD (rG=0.46, P=0.02), although this did not survive multiple comparison testing. None of the other six brain regions studied were genetically correlated and amygdala volume heritability was too low for analysis. Using PRS analysis, no regional volumetric PRS demonstrated a significant association with MDD or recurrent MDD. MR analysis in hippocampal volume and MDD identified no causal association, however, BUHMBOX analysis identified genetic subgrouping in GS:SFHS MDD cases only (P=0.00281). In this study, we provide some evidence that hippocampal volume and MDD may share genetic architecture in a subgroup of individuals, albeit the genetic correlation did not survive multiple testing correction and genetic subgroup heterogeneity was not replicated. In contrast, we found no evidence to support a shared genetic architecture between MDD and other regional subcortical volumes or ICV.

Common polygenic risk for autism spectrum disorder (ASD) is associated with cognitive ability in the general population.

Cognitive impairment is common among individuals diagnosed with autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD). It has been suggested that some aspects of intelligence are preserved or even superior in people with ASD compared with controls, but consistent evidence is lacking. Few studies have examined the genetic overlap between cognitive ability and ASD/ADHD. The aim of this study was to examine the polygenic overlap between ASD/ADHD and cognitive ability in individuals from the general population. Polygenic risk for ADHD and ASD was calculated from genome-wide association studies of ASD and ADHD conducted by the Psychiatric Genetics Consortium. Risk scores were created in three independent cohorts: Generation Scotland Scottish Family Health Study (GS:SFHS) (n=9863), the Lothian Birth Cohorts 1936 and 1921 (n=1522), and the Brisbane Adolescent Twin Sample (BATS) (n=921). We report that polygenic risk for ASD is positively correlated with general cognitive ability (beta=0.07, P=6 × 10(-7), r(2)=0.003), logical memory and verbal intelligence in GS:SFHS. This was replicated in BATS as a positive association with full-scale intelligent quotient (IQ) (beta=0.07, P=0.03, r(2)=0.005). We did not find consistent evidence that polygenic risk for ADHD was associated with cognitive function; however, a negative correlation with IQ at age 11 years (beta=-0.08, Z=-3.3, P=0.001) was observed in the Lothian Birth Cohorts. These findings are in individuals from the general population, suggesting that the relationship between genetic risk for ASD and intelligence is partly independent of clinical state. These data suggest that common genetic variation relevant for ASD influences general cognitive ability.

708 Common and 2010 rare DISC1 locus variants identified in 1542 subjects: analysis for association with psychiatric disorder and cognitive traits.

A balanced t(1;11) translocation that transects the Disrupted in schizophrenia 1 (DISC1) gene shows genome-wide significant linkage for schizophrenia and recurrent major depressive disorder (rMDD) in a single large Scottish family, but genome-wide and exome sequencing-based association studies have not supported a role for DISC1 in psychiatric illness. To explore DISC1 in more detail, we sequenced 528 kb of the DISC1 locus in 653 cases and 889 controls. We report 2718 validated single-nucleotide polymorphisms (SNPs) of which 2010 have a minor allele frequency of <1%. Only 38% of these variants are reported in the 1000 Genomes Project European subset. This suggests that many DISC1 SNPs remain undiscovered and are essentially private. Rare coding variants identified exclusively in patients were found in likely functional protein domains. Significant region-wide association was observed between rs16856199 and rMDD (P=0.026, unadjusted P=6.3 × 10(-5), OR=3.48). This was not replicated in additional recurrent major depression samples (replication P=0.11). Combined analysis of both the original and replication set supported the original association (P=0.0058, OR=1.46). Evidence for segregation of this variant with disease in families was limited to those of rMDD individuals referred from primary care. Burden analysis for coding and non-coding variants gave nominal associations with diagnosis and measures of mood and cognition. Together, these observations are likely to generalise to other candidate genes for major mental illness and may thus provide guidelines for the design of future studies.

Interacting haplotypes at the NPAS3 locus alter risk of schizophrenia and bipolar disorder.

The neuronal PAS domain 3 (NPAS3) gene encodes a neuronal transcription factor that is implicated in psychiatric disorders by the identification of a human chromosomal translocation associated with schizophrenia and a mouse knockout model with behavioural and hippocampal neurogenesis defects. To determine its contribution to the risk of psychiatric illness in the general population, we genotyped 70 single-nucleotide polymorphisms across the NPAS3 gene in 368 individuals with bipolar disorder, 386 individuals with schizophrenia and 455 controls. Modestly significant single-marker and global and individual haplotypes were identified in four discrete regions of the gene. The presence of both risk and protective haplotypes at each of these four regions indicated locus and allelic heterogeneity within NPAS3 and suggested a model whereby interactions between variants across the gene might contribute to susceptibility to illness. This was supported by predicting the most likely haplotype for each individual at each associated region and then calculating an NPAS3-mediated 'net genetic load' value. This value differed significantly from controls for both bipolar disorder (P=0.0000010) and schizophrenia (P=0.0000012). Logistic regression analysis also confirmed the combinatorial action of the four associated regions on disease risk. In addition, sensitivity/specificity plots showed that the extremes of the genetic loading distribution possess the greatest predictive power-a feature suggesting multiplicative allele interaction. These data add to recent evidence that the combinatorial analysis of a number of relatively small effect size haplotypes may have significant power to predict an individual's risk of a complex genetic disorder such as psychiatric illness.

Association analysis of the chromosome 4p15-p16 candidate region for bipolar disorder and schizophrenia.

Several independent linkage studies have identified chromosome 4p15-p16 as a putative region of susceptibility for bipolar disorder (BP), schizophrenia (SCZ) and related phenotypes. Previously, we identified two subregions (B and D) of the 4p15-p16 region that are shared by three of four 4p-linked families examined. Here, we describe a large-scale association analysis of regions B and D (3.8 and 4.5 Mb, respectively). We selected 408 haplotype-tagging single nucleotide polymorphisms (SNPs) on a block-by-block basis from the International HapMap project and tested them in 368 BP, 386 SCZ and 458 control individuals. Nominal significance thresholds were determined using principal component analysis as implemented in the program SNPSpD. In region B, overlapping SNPs and haplotypes met the region-wide threshold (P

Association of Neuregulin 1 with schizophrenia and bipolar disorder in a second cohort from the Scottish population.

Neuregulin 1 (NRG1) is a strong candidate for involvement in the aetiology of schizophrenia. A haplotype, initially identified as showing association in the Icelandic and Scottish populations, has shown a consistent effect size in multiple European populations. Additionally, NRG1 has been implicated in susceptibility to bipolar disorder. In this first study to select markers systematically on the basis of linkage disequilibrium across the entire NRG1 gene, we used haplotype-tagging single-nucleotide polymorphisms to identify single markers and haplotypes associated with schizophrenia and bipolar disorder in an independently ascertained Scottish population. Haplotypes in two regions met an experiment-wide significance threshold of P=0.0016 (Nyholt's SpD) and were permuted to correct for multiple testing. Region A overlaps with the Icelandic haplotype and shows nominal association with schizophrenia (P=0.00032), bipolar disorder (P=0.0011), and the combined case group (P=0.0017). This region includes the 5' exon of the NRG1 GGF2 isoform and overlaps the expressed sequence tag (EST) cluster Hs.97362. However, no haplotype in Region A remains significant after permutation analysis (P>0.05). Region B contains a haplotype associated with both schizophrenia (P=0.00014), and the combined case group (P=0.000062), although it does not meet Nyholt's threshold in bipolar disorder alone (P=0.0022). This haplotype remained significant after permutation analysis in both the schizophrenia and combined case groups (P=0.024 and P=0.016, respectively). It spans a approximately 136 kb region that includes the coding sequence of the sensory and motor neuron derived factor (SMDF) isoform and 3' exons of all other known NRG1 isoforms. Our study identifies a new of NRG1 region involved in schizophrenia and bipolar disorder in the Scottish population.

Cytogenetic and genetic evidence supports a role for the kainate-type glutamate receptor gene, GRIK4, in schizophrenia and bipolar disorder.

In the search for the biological causes of schizophrenia and bipolar disorder, glutamate neurotransmission has emerged as one of a number of candidate processes and pathways where underlying gene deficits may be present. The analysis of chromosomal rearrangements in individuals diagnosed with neuropsychiatric disorders is an established route to candidate gene identification in both Mendelian and complex disorders. Here we describe a set of genes disrupted by, or proximal to, chromosomal breakpoints (2p12, 2q31.3, 2q21.2, 11q23.3 and 11q24.2) in a patient where chronic schizophrenia coexists with mild learning disability (US: mental retardation). Of these disrupted genes, the most promising candidate is a member of the kainate-type ionotropic glutamate receptor family, GRIK4 (KA1). A subsequent systematic case-control association study on GRIK4 assessed its contribution to psychiatric illness in the karyotypically normal population. This identified two discrete regions of disease risk within the GRIK4 locus: three single single nucleotide polymorphism (SNP) markers with a corresponding underlying haplotype associated with susceptibility to schizophrenia (P=0.0005, odds ratio (OR) of 1.453, 95% CI 1.182-1.787) and two single SNP markers and a haplotype associated with a protective effect against bipolar disorder (P=0.0002, OR of 0.624, 95% CI 0.485-0.802). After permutation analysis to correct for multiple testing, schizophrenia and bipolar disorder haplotypes remained significant (P=0.0430, s.e. 0.0064 and P=0.0190, s.e. 0.0043, respectively). We propose that these convergent cytogenetic and genetic findings provide molecular evidence for common aetiologies for different psychiatric conditions and further support the 'glutamate hypothesis' of psychotic illness.

Association analysis of the chromosome 4p-located G protein-coupled receptor 78 (GPR78) gene in bipolar affective disorder and schizophrenia.

The orphan G protein-coupled receptor 78 (GPR78) gene lies within a region of chromosome 4p where we have previously shown linkage to bipolar affective disorder (BPAD) in a large Scottish family. GPR78 was screened for single-nucleotide polymorphisms (SNPs) and a linkage disequilibrium map was constructed. Six tagging SNPs were selected and tested for association on a sample of 377 BPAD, 392 schizophrenia (SCZ) and 470 control individuals. Using standard chi(2) statistics and a backwards logistic regression approach to adjust for the effect of sex, SNP rs1282, located approximately 3 kb upstream of the coding region, was identified as a potentially important variant in SCZ (chi(2) P=0.044; LRT P=0.065). When the analysis was restricted to females, the strength of association increased to an uncorrected allele P-value of 0.015 (odds ratios (OR)=1.688, 95% confidence intervals (CI): 1.104-2.581) and uncorrected genotype P-value of 0.015 (OR=5.991, 95% CI: 1.545-23.232). Under the recessive model, the genotype P-value improved further to 0.005 (OR=5.618, 95% CI: 1.460-21.617) and remained significant after correcting for multiple testing (P=0.017). No single-marker association was detected in the SCZ males, in the BPAD individuals or with any other SNP. Haplotype analysis of the case-control samples revealed several global and individual haplotypes, with P-values <0.05, all but one of which contained SNP rs1282. After correcting for multiple testing, two haplotypes remained significant in both the female BPAD individuals (P=0.038 and 0.032) and in the full sample of affected female individuals (P=0.044 and 0.033). Our results provide preliminary evidence for the involvement of GPR78 in susceptibility to BPAD and SCZ in the Scottish population.

Association between genotype at an exonic SNP in DISC1 and normal cognitive aging.

DISC1 is expressed in the hippocampus and has been identified as a possible genetic risk factor for both schizophrenia and bipolar disorder. These psychiatric illnesses are associated with impaired learning and memory. This study investigates the association of variation in DISC1 with cognitive function on the same general mental ability test (Moray House Test) at age 11 and age 79, and cognitive change between ages 11 and 79, in 425 people from the Lothian Birth Cohort 1921 (LBC1921). Tests of memory, non-verbal reasoning and executive function were also administered at age 79. The effect of genotype at a non-synonymous single nucleotide polymorphism in exon 11, rs821616, was studied. There was no direct effect of DISC1 genotype on any cognitive measure. However, there was a significant DISC1 genotype by sex interaction on Moray House Test scores at age 79, both before and after adjustment for cognitive ability at age 11 (p = 0.034 and 0.043, respectively). Women homozygous for the Cys allele had significantly lower cognitive ability scores than men at age 79, p = 0.003. Variation in DISC1 may therefore affect cognitive aging especially in women.

Association between the TRAX/DISC locus and both bipolar disorder and schizophrenia in the Scottish population.

The Translin-associated factor X/Disrupted in Schizophrenia 1 (TRAX/DISC) region was first implicated as a susceptibility locus for schizophrenia by analysis of a large Scottish family in which a t(1;11) translocation cosegregates with schizophrenia, bipolar disorder and recurrent major depression. We now report evidence for association between bipolar disorder and schizophrenia and this locus in the general Scottish population. A systematic study of linkage disequilibrium in a representative sample of the Scottish population was undertaken across the 510 kb of TRAX and DISC1. SNPs representing each haplotype block were selected for case-control association studies of both schizophrenia and bipolar disorder. Significant association with bipolar disorder in women P=0.00026 (P=0.0016 in men and women combined) was detected in a region of DISC1. This same region also showed nominally significant association with schizophrenia in both men and women combined, P=0.0056. Two further regions, one in TRAX and the second in DISC1, showed weaker evidence for sex-specific associations of individual haplotypes with bipolar disorder in men and women respectively, P<0.01. Only the association between bipolar women and DISC1 remained significant after correction for multiple testing. This result provides further supporting evidence for DISC1 as a susceptibility factor for both bipolar disorder and schizophrenia, consistent with the diagnoses in the original Scottish translocation family.

Sex-specific association between bipolar affective disorder in women and GPR50, an X-linked orphan G protein-coupled receptor.

GPR50 is an orphan G protein-coupled receptor (GPCR) located on Xq28, a region previously implicated in multiple genetic studies of bipolar affective disorder (BPAD). Allele frequencies of three polymorphisms in GPR50 were compared in case-control studies between subjects with BPAD (264), major depressive disorder (MDD) (226), or schizophrenia (SCZ) (263) and ethnically matched controls (562). Significant associations were found between an insertion/deletion polymorphism in exon 2 and both BPAD (P=0.0070), and MDD (P=0.011) with increased risk associated with the deletion variant (GPR50(Delta502-505)). When the analysis was restricted to female subjects, the associations with BPAD and MDD increased in significance (P=0.00023 and P=0.0064, respectively). Two other single-nucleotide polymorphisms (SNPs) tested within this gene showed associations between: the female MDD group and an SNP in exon 2 (P=0.0096); and female SCZ and an intronic SNP (P=0.0014). No association was detected in males with either MDD, BPAD or SCZ. These results suggest that GPR50(Delta502-505), or a variant in tight linkage disequilibrium with this polymorphism, is a sex-specific risk factor for susceptibility to bipolar disorder, and that other variants in the gene may be sex-specific risk factors in the development of schizophrenia.

Clinical interventions provided by doctor of pharmacy students.

OBJECTIVE: To assess the types, perceived benefit, and cost impact of the interactions provided by two-year post-B.S. Pharm.D. students on clerkship rotations. DESIGN: Information was obtained through voluntary reporting by students on a standardized data collection form. Cost analysis and peer review were performed on a subset of interventions. SETTING: The setting of the study included hospital clerkship sites (general medicine and specialty rotations) and an ambulatory care site (general medicine). PARTICIPANTS: Six second-year Pharm.D. students. RESULTS: Reports that were completed totaled 951, including 612 intervention, 335 information, and 4 unknown events. Most events were drug related and student initiated. Follow-up was predominantly to physicians. Intervention events primarily involved changes in drug therapy regimens (63.5 percent), changes in dose (29.5 percent), and identification of potential adverse drug reactions (7 percent). Acceptance rate of recommendations was 78.7 percent. Antibiotics, cardiovascular agents, and central nervous system drugs accounted for 55.5 percent of all interventions. Almost 80 percent of disease states encountered included cardiovascular, infectious, neurologic, pulmonary, gastrointestinal, and endocrine diseases. Overall, peer review scores tended to show a positive impact, with physician scoring higher than pharmacy faculty scoring. Medication-related costs were reduced modestly by accepted student interventions. CONCLUSIONS: This study demonstrates substantial clinical involvement of two-year post-B.S. Pharm.D. students on clerkships. The results indicate that the curriculum of Pharm.D. programs should emphasize cardiology, infectious disease, neurology, and gerontology.