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Basing on the assumption that frontotemporal lobar degeneration (FTLD), schizophrenia and bipolar disorder (BPD) might share common aetiological mechanisms, we analyzed genetic variation in the FTLD risk gene progranulin (GRN) in a German population of patients with schizophrenia (n = 271) or BPD (n = 237) as compared with 574 age-, gender- and ethnicity-matched controls. Furthermore, we measured plasma progranulin levels in 26 German BPD patients as well as in 61 Italian BPD patients and 29 matched controls.A significantly decreased allelic frequency of the minor versus the wild-type allele was observed for rs2879096 (23.2 versus 34.2%, P<0.001, OR:0.63, 95%CI:0.49-0.80), rs4792938 (30.7 versus 39.7%, P = 0.005, OR: 0.70, 95%CI: 0.55-0.89) and rs5848 (30.3 versus 36.8, P = 0.007, OR: 0.71, 95%CI: 0.56-0.91). Mean±SEM progranulin plasma levels were significantly decreased in BPD patients, either Germans or Italians, as compared with controls (89.69±3.97 and 116.14±5.80 ng/ml, respectively, versus 180.81±18.39 ng/ml P<0.001) and were not correlated with age.In conclusion, GRN variability decreases the risk to develop BPD and schizophrenia, and progranulin plasma levels are significantly lower in BPD patients than in controls. Nevertheless, a larger replication analysis would be needed to confirm these preliminary results.

Several linkage analyses implicated the chromosome 9q22 region in attention deficit/hyperactivity disorder (ADHD), a neurodevelopmental disease with remarkable persistence into adulthood. This locus contains the brain-expressed GTP-binding RAS-like 2 gene (DIRAS2) thought to regulate neurogenesis. As DIRAS2 is a positional and functional ADHD candidate gene, we conducted an association study in 600 patients suffering from adult ADHD (aADHD) and 420 controls. Replication samples consisted of 1035 aADHD patients and 1381 controls, as well as 166 families with a child affected from childhood ADHD. Given the high degree of co-morbidity with ADHD, we also investigated patients suffering from bipolar disorder (BD) (n=336) or personality disorders (PDs) (n=622). Twelve single-nucleotide polymorphisms (SNPs) covering the structural gene and the transcriptional control region of DIRAS2 were analyzed. Four SNPs and two haplotype blocks showed evidence of association with ADHD, with nominal p-values ranging from p=0.006 to p=0.05. In the adult replication samples, we obtained a consistent effect of rs1412005 and of a risk haplotype containing the promoter region (p=0.026). Meta-analysis resulted in a significant common OR of 1.12 (p=0.04) for rs1412005 and confirmed association with the promoter risk haplotype (OR=1.45, p=0.0003). Subsequent analysis in nuclear families with childhood ADHD again showed an association of the promoter haplotype block (p=0.02). rs1412005 also increased risk toward BD (p=0.026) and cluster B PD (p=0.031). Additional SNPs showed association with personality scores (p=0.008-0.048). Converging lines of evidence implicate genetic variance in the promoter region of DIRAS2 in the etiology of ADHD and co-morbid impulsive disorders.

Recently, several genome-wide association studies (GWAS) on bipolar disorder (BPD) suggested novel risk genes. However, only few of them were followed up and further, the specificity of these genes is even more elusive. To address these issues, we genotyped SNPs in ANK3, CACNA1C, CMTM8, DGKH, EGFR, and NPAS3, which were significantly associated with BPD in previous GWAS, in a sample of 380 BPD patients. Replicated SNPs were then followed up in patients suffering from unipolar depression (UPD; n=387) or adult attention-deficit/hyperactivity disorder (aADHD; n=535). While we could not confirm an association of ANK3, CACNA1C, and EGFR with BPD, 10 SNPs in DGKH, CMTM8, and NPAS3 were nominally associated with disease, with two DGKH markers surviving correction for multiple testing. When these were followed up in UPD and aADHD, seven DGKH SNPs were also associated with UPD, while one SNP each in NPAS3 and CMTM8 and four in DGKH were linked to aADHD. Furthermore, a DGKH haplotype consisting of rs994856/rs9525580/rs9525584 GAT was associated with all disorders tested, while the complementary AGC haplotype was protective. The corresponding haploblock spans a 27-kb region covering exons coding for amino acids 65-243, and thus might include functional variants yet to be identified. We demonstrate an association of DGKH with BPD, UPD, and aADHD by applying a two-stage design. These disorders share the feature of mood instability, so that this phenotype might be associated with genetic variation in DGKH.

Cognitive deficits in tasks involving the prefrontal cortex such as working memory or verbal fluency are a key component of schizophrenia. This led to the hypofrontality hypothesis of schizophrenia, which is widely accepted even though molecular underpinnings are elusive. While disturbances of glutamatergic neurotransmission might play a role, other components have rarely been investigated. Recently, the promoter region of nitric oxide (NO) synthase-I (NOS-I, encoded by the gene NOS1), impacting on prefrontal glutamate transmission, has repeatedly been associated with schizophrenia. We thus tested whether an associated schizophrenia risk variant (rs41279104), leading to reduced expression of the transcript, influences prefrontal brain functioning. Forty-three patients suffering from chronic schizophrenia and 44 controls were genotyped for NOS1 rs41279104 and investigated by means of functional near-infrared spectroscopy (fNIRS), while completing a working-memory task (2-back test) and a verbal fluency test (VFT). After matching for genotype, behavioural and brain activation data of 26 patients and 28 comparable controls were correlated to rs41279104. Healthy controls showed significant activation of large parts of the lateral prefrontal cortex during both tasks, whereas task-related changes in oxygenation were significantly reduced in patients. Schizophrenia patients also performed worse in both tasks. The NOS1 schizophrenia risk genotype rs41279104 AA/AG was associated with slower reaction time in the 2-back task, as well as with reduced right-hemispheric activation of the frontal cortex for VFT in patients only. Our fNIRS data extend previous studies suggesting disturbed prefrontal functioning in schizophrenia and suggest that genetic variation of NOS1 has a role in cognitive dysfunction, probably by mediating glutamatergic tone.

The comprehensive and stress-free assessment of various aspects of learning and memory is a prerequisite to evaluate mouse models for neuropsychiatric disorders such as Alzheimer's disease or attention deficit/hyperactivity disorder (ADHD). COGITAT is an automated holeboard system allowing simultaneous assessment of spatial working and reference-memory performance which we have adapted in this study to enable its usage with mice. The holeboard apparatus consists of an open-field chamber with a 25-hole floor insert, each hole being monitored by infrared light beams, located on three different levels, allowing the distinction between visits of holes, i.e. the animal reaches the bottom of the hole, or inspections, which means only superficial exploration of the hole. Across trials, animals learn a pattern of five baited holes. Here, we show that C57BL/6 mice readily acquire this task within 5 days when submitted to six trials per day. A number of individual parameters - overall exploratory activity, number of visits into or inspections of holes, number of baited, unbaited, or previously baited holes visited or inspected, reinspections of or revisits into any holes, number of pellets eaten, time to find pellets, and reference and working memory errors-are obtained simultaneously and results are immediately available after the end of each experiment. The muscarinic antagonist scopolamine impaired task performance, while the cognitive enhancer metrifonate (an acetylcholinesterase inhibitor) reduced error rates. Overall, our data indicate that this spatial learning task will be useful to characterize spatial memory in various genetic or pharmacological mouse models., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Context: Although psychiatric disorders are, to date, diagnosed on the basis of behavioral symptoms and course of illness, the interest in neurobiological markers of psychiatric disorders has grown substantially in recent years. However, current classification approaches are mainly based on data from a single biomarker, making it difficult to predict disorders characterized by complex patterns of symptoms., Objective: To integrate neuroimaging data associated with multiple symptom-related neural processes and demonstrate their utility in the context of depression by deriving a predictive model of brain activation., Design: Two groups of participants underwent functional magnetic resonance imaging during 3 tasks probing neural processes relevant to depression., Setting: Participants were recruited from the local population by use of advertisements; participants with depression were inpatients from the Department of Psychiatry, Psychosomatics, and Psychotherapy at the University of Wuerzburg, Wuerzburg, Germany., Participants: We matched a sample of 30 medicated, unselected patients with depression by age, sex, smoking status, and handedness with 30 healthy volunteers., Main Outcome Measure: Accuracy of single-subject classification based on whole-brain patterns of neural responses from all 3 tasks., Results: Integrating data associated with emotional and affective processing substantially increases classification accuracy compared with single classifiers. The predictive model identifies a combination of neural responses to neutral faces, large rewards, and safety cues as nonredundant predictors of depression. Regions of the brain associated with overall classification comprise a complex pattern of areas involved in emotional processing and the analysis of stimulus features., Conclusions: Our method of integrating neuroimaging data associated with multiple, symptom-related neural processes can provide a highly accurate algorithm for classification. The integrated biomarker model shows that data associated with both emotional and reward processing are essential for a highly accurate classification of depression. In the future, large-scale studies will need to be conducted to determine the practical applicability of our algorithm as a biomarker-based diagnostic aid.

Background: The Abelson helper integration-1 (AHI1) gene is required for both cerebellar and cortical development in humans. While the accelerated evolution of AHI1 in the human lineage indicates a role in cognitive (dys)function, a linkage scan in large pedigrees identified AHI1 as a positional candidate for schizophrenia. To further investigate the contribution of AHI1 to the susceptibility of schizophrenia, we evaluated the effect of AHI1 variation on the vulnerability to psychosis in two samples from Spain and Germany., Methodology/principal Findings: 29 single-nucleotide polymorphisms (SNPs) located in a genomic region including the AHI1 gene were genotyped in two samples from Spain (280 patients with psychotic disorders; 348 controls) and Germany (247 patients with schizophrenic disorders; 360 controls). Allelic, genotypic and haplotype frequencies were compared between cases and controls in both samples separately, as well as in the combined sample. The effect of genotype on several psychopathological measures (BPRS, KGV, PANSS) assessed in a Spanish subsample was also evaluated. We found several significant associations in the Spanish sample. Particularly, rs7750586 and rs911507, both located upstream of the AHI1 coding region, were found to be associated with schizophrenia in the analysis of genotypic (p = 0.0033, and 0.031, respectively) and allelic frequencies (p = 0.001 in both cases). Moreover, several other risk and protective haplotypes were detected (0.006

Tetraspanins affect protein trafficking and are known to influence a wide variety of physiologic processes. Recently, single nucleotide polymorphisms (SNPs) of the tetraspanin gene TSPAN8 were found among the best ranked markers of genome wide association studies on bipolar disorder (BPD) (rs1705236) and type-2 diabetes, but functional consequences remained largely unknown. In the present study, we examined 13 tagging SNPs covering the TSPAN8 gene, the intronic TSPAN8 SNP rs1705236 as well as two non-synonymous (ns) SNPs in schizophrenia (SCZ) and BPD samples. In our analysis setting, we were not able to replicate the association of rs1705236 with BPD, nor did we find an association with SCZ. In the TSPAN8 upstream transcriptional control region however, we found rs4500567 to be associated with BPD. In contrast, in SCZ the nsSNP rs3763978 was associated with disease. The significance of both associations withstood conservative Bonferroni correction. In an attempt to link the polymorphisms to functional consequences, we performed an allele-specific in silico mapping of transcription factor binding sites around rs4500567 and predicted the tolerance of the Gly73Ala exchange caused by rs3763978. The results argue for a differential promoter activity specific for the variant associated with BPD, but impaired protein functionality in SCZ. This suggests that TSPAN8 contributes to both diseases, yet with different underlying mechanisms: regulatory versus structural. Similar phenomena might also occur in other risk genes for both BPD and SCZ, providing a molecular basis for the genetic overlap of both entities.

For more than half a decade, lithium has been successfully used to treat bipolar disorder. Worldwide, it is considered the first-line mood stabilizer. Apart from its proven antimanic and prophylactic effects, considerable evidence also suggests an antisuicidal effect in affective disorders. Lithium is also effectively used to augment antidepressant drugs in the treatment of refractory major depressive episodes and prevent relapses in recurrent unipolar depression. In contrast to many psychiatric drugs, lithium has outlasted various pharmacotherapeutic 'fashions', and remains an indispensable element in contemporary psychopharmacology. Nevertheless, data from pharmacogenetic studies of lithium are comparatively sparse, and these studies are generally characterized by small sample sizes and varying definitions of response. Here, we present an international effort to elucidate the genetic underpinnings of lithium response in bipolar disorder. Following an initiative by the International Group for the Study of Lithium-Treated Patients (www.IGSLI.org) and the Unit on the Genetic Basis of Mood and Anxiety Disorders at the National Institute of Mental Health,lithium researchers from around the world have formed the Consortium on Lithium Genetics (www.ConLiGen.org) to establish the largest sample to date for genome-wide studies of lithium response in bipolar disorder, currently comprising more than 1,200 patients characterized for response to lithium treatment. A stringent phenotype definition of response is one of the hallmarks of this collaboration. ConLiGen invites all lithium researchers to join its efforts., (Copyright 2010 S. Karger AG, Basel.)