The polygenic basis of relapse after a first episode of schizophrenia

Little is known about genetic predisposition to relapse. Previous studies have linked cognitive and psychopathological (mainly schizophrenia and bipolar disorder) polygenic risk scores (PRS) with clinical manifestations of the disease. This study aims to explore the potential role of PRS from major mental disorders and cognition on schizophrenia relapse. 114 patients recruited in the 2EPs Project were included (56 patients who had not experienced relapse after 3 years of enrollment and 58 patients who relapsed during the 3-year follow-up). PRS for schizophrenia (PRS-SZ), bipolar disorder (PRS-BD), education attainment (PRS-EA) and cognitive performance (PRS-CP) were used to assess the genetic risk of schizophrenia relapse.Patients with higher PRS-EA, showed both a lower risk (OR=0.29, 95% CI [0.11-0.73]) and a later onset of relapse (30.96± 1.74 vs. 23.12± 1.14 months, p=0.007. Our study provides evidence that the genetic burden of neurocognitive function is a potentially predictors of relapse that could be incorporated into future risk prediction models. Moreover, appropriate treatments for cognitive symptoms appear to be important for improving the long-term clinical outcome of relapse.

T-cadherin is a novel regulator of pericyte function during angiogenesis

Pericytes are mural cells that play an important role in regulation of angiogenesis and endothelial function. Cadherins are a superfamily of adhesion molecules mediating Ca²⁺-dependent homophilic cell-cell interactions that control morphogenesis and tissue remodeling. To date, classical N-cadherin is the only cadherin described on pericytes. Here, we demonstrate that pericytes also express T-cadherin (H-cadherin, CDH13), an atypical glycosyl-phosphatidylinositol (GPI)-anchored member of the superfamily that has previously been implicated in regulation of neurite guidance, endothelial angiogenic behavior, and smooth muscle cell differentiation and progression of cardiovascular disease. The aim of the study was to investigate T-cadherin function in pericytes. Expression of T-cadherin in pericytes from different tissues was performed by immunofluorescence analysis. Using lentivirus-mediated gain-of-function and loss-of-function in cultured human pericytes, we demonstrate that T-cadherin regulates pericyte proliferation, migration, invasion, and interactions with endothelial cells during angiogenesis in vitro and in vivo. T-cadherin effects are associated with the reorganization of the cytoskeleton, modulation of cyclin D1, α-smooth muscle actin (αSMA), integrin β3, metalloprotease MMP1, and collagen expression levels, and involve Akt/GSK3β and ROCK intracellular signaling pathways. We also report the development of a novel multiwell 3-D microchannel slide for easy analysis of sprouting angiogenesis from a bioengineered microvessel in vitro. In conclusion, our data identify T-cadherin as a novel regulator of pericyte function and support that it is required for pericyte proliferation and invasion during active phase of angiogenesis, while T-cadherin loss shifts pericytes toward the myofibroblast state rendering them unable to control endothelial angiogenic behavior.

A polygenic approach to the association between smoking and schizophrenia

Smoking prevalence in schizophrenia is considerably larger than in general population, playing an important role in early mortality. We compared the polygenic contribution to smoking in schizophrenic patients and controls to assess if genetic factors may explain the different prevalence. Polygenic risk scores (PRSs) for smoking initiation and four genetically correlated traits were calculated in 1108 schizophrenic patients (64.4% smokers) and 1584 controls (31.1% smokers). PRSs for smoking initiation, educational attainment, body mass index and age at first birth were associated with smoking in patients and controls, explaining a similar percentage of variance in both groups. Attention-deficit hyperactivity disorder (ADHD) PRS was associated with smoking only in schizophrenia. This association remained significant after adjustment by psychiatric cross-disorder PRS. A PRS combining all the traits was more explanative than smoking initiation PRS alone, indicating that genetic susceptibility to the other traits plays an additional role in smoking behaviour. Smoking initiation PRS was also associated with schizophrenia in the whole sample, but the significance was lost after adjustment for smoking status. This same pattern was observed in the analysis of specific SNPs at the CHRNA5-CHRNA3-CHRNB4 cluster associated with both traits. Overall, the results indicate that the same genetic factors are involved in smoking susceptibility in schizophrenia and in general population and are compatible with smoking acting, directly or indirectly, as a risk factor for schizophrenia that contributes to the high prevalence of smoking in these patients. The contrasting results for ADHD PRS may be related to higher ADHD symptomatology in schizophrenic patients.

Haploinsufficiency of the Attention-Deficit/Hyperactivity Disorder Risk Gene St3gal3 in Mice Causes Alterations in Cognition and Expression of Genes Involved in Myelination and Sialylation

Genome wide association meta-analysis identified ST3GAL3, a gene encoding the beta-galactosidase-alpha-2,3-sialyltransferase-III, as a risk gene for attention-deficit/hyperactivity disorder (ADHD). Although loss-of-function mutations in ST3GAL3 are implicated in non-syndromic autosomal recessive intellectual disability (NSARID) and West syndrome, the impact of ST3GAL3 haploinsufficiency on brain function and the pathophysiology of neurodevelopmental disorders (NDDs), such as ADHD, is unknown. Since St3gal3 null mutant mice display severe developmental delay and neurological deficits, we investigated the effects of partial inactivation of St3gal3 in heterozygous (HET) knockout (St3gal3^±) mice on behavior as well as expression of markers linked to myelination processes and sialylation pathways. Our results reveal that male St3gal3 HET mice display cognitive deficits, while female HET animals show increased activity, as well as increased cognitive control, compared to their wildtype littermates. In addition, we observed subtle alterations in the expression of several markers implicated in oligodendrogenesis, myelin formation, and protein sialylation as well as cell adhesion/synaptic target glycoproteins of ST3GAL3 in a brain region- and/or sex-specific manner. Taken together, our findings indicate that haploinsufficiency of ST3GAL3 results in a sex-dependent alteration of cognition, behavior and markers of brain plasticity.

Generation of induced pluripotent stem cell (iPSC) lines carrying a heterozygous (UKWMPi002-A-1) and null mutant knockout (UKWMPi002-A-2) of Cadherin 13 associated with neurodevelopmental disorders using CRISPR/Cas9

Fibroblasts isolated from a skin biopsy of a healthy 46-year-old female were infected with Sendai virus containing the Yamanaka factors to produce transgene-free human induced pluripotent stem cells (iPSCs). CRISPR/Cas9 was used to generate isogenic cell lines with a gene dose-dependent deficiency of CDH13, a risk gene associated with neurodevelopmental and psychiatric disorders. Thereby, a heterozygous CDH13 knockout (CDH13^+/-) and a CDH13 null mutant (CDH13^-/-) iPSC line was obtained. All three lines showed expression of pluripotency-associated markers, the ability to differentiate into cells of the three germ layers in vitro, and a normal female karyotype.

Transcriptome profiling in adult attention-deficit hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with an estimated heritability of around 70%. Although the largest genome-wide association study (GWAS) meta-analysis on ADHD identified independent loci conferring risk to the disorder, the molecular mechanisms underlying the genetic basis of the disorder remain to be elucidated. To explore ADHD biology, we ran a two-step transcriptome profiling in peripheral blood mononuclear cells (PBMCs) of 143 ADHD subjects and 169 healthy controls. Through this exploratory study we found eight differentially expressed genes in ADHD. These results highlight promising candidate genes and gene pathways for ADHD and support the use of peripheral tissues to assess gene expression signatures for ADHD.

Shared genetic background between children and adults with attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterized by age-inappropriate symptoms of inattention, impulsivity, and hyperactivity that persist into adulthood in the majority of the diagnosed children. Despite several risk factors during childhood predicting the persistence of ADHD symptoms into adulthood, the genetic architecture underlying the trajectory of ADHD over time is still unclear. We set out to study the contribution of common genetic variants to the risk for ADHD across the lifespan by conducting meta-analyses of genome-wide association studies on persistent ADHD in adults and ADHD in childhood separately and jointly, and by comparing the genetic background between them in a total sample of 17,149 cases and 32,411 controls. Our results show nine new independent loci and support a shared contribution of common genetic variants to ADHD in children and adults. No subgroup heterogeneity was observed among children, while this group consists of future remitting and persistent individuals. We report similar patterns of genetic correlation of ADHD with other ADHD-related datasets and different traits and disorders among adults, children, and when combining both groups. These findings confirm that persistent ADHD in adults is a neurodevelopmental disorder and extend the existing hypothesis of a shared genetic architecture underlying ADHD and different traits to a lifespan perspective.

Serotonin (5-HT) neuron-specific inactivation of Cadherin-13 impacts 5-HT system formation and cognitive function

Genome-wide screening approaches identified the cell adhesion molecule Cadherin-13 (CDH13) as a risk factor for neurodevelopmental disorders, nevertheless the contribution of CDH13 to the disease mechanism remains obscure. CDH13 is involved in neurite outgrowth and axon guidance during early brain development and we previously provided evidence that constitutive CDH13 deficiency influences the formation of the raphe serotonin (5-HT) system by modifying neuron-radial glia interaction. Here, we dissect the specific impact of CDH13 on 5-HT system development and function using a 5-HT neuron-specific Cdh13 knockout mouse model (conditional Cdh13 knockout, Cdh13 cKO). Our results show that exclusive inactivation of CDH13 in 5-HT neurons selectively increases 5-HT neuron density in the embryonic dorsal raphe, with persistence into adulthood, and serotonergic innervation of the developing prefrontal cortex. At the behavioral level, adult Cdh13 cKO mice display delayed acquisition of several learning tasks and a subtle impulsive-like phenotype, with decreased latency in a sociability paradigm alongside with deficits in visuospatial memory. Anxiety-related traits were not observed in Cdh13 cKO mice. Our findings further support the critical role of CDH13 in the development of dorsal raphe 5-HT circuitries, a mechanism that may underlie specific clinical features observed in neurodevelopmental disorders.

Early-life stress impairs developmental programming in Cadherin 13 (CDH13)-deficient mice

OBJECTIVE

Cadherin-13 (CDH13), a member of the calcium-dependent cell adhesion molecule family, has been linked to neurodevelopmental disorders, including autism spectrum (ASD) and attention-deficit/hyperactivity (ADHD) disorders, but also to depression. In the adult brain, CDH13 expression is restricted e.g. to the presynaptic compartment of inhibitory GABAergic synapses in the hippocampus and Cdh13 knockout mice show an increased inhibitory drive onto hippocampal CA1 pyramidal neurons, leading to a shift in excitatory/inhibitory balance. CDH13 is also moderating migration of serotonergic neurons in the dorsal raphe nucleus, establishing projections preferentially to the thalamus and cerebellum during brain development. Furthermore, CDH13 is upregulated by chronic stress as well as in depression, suggesting a role in early-life adaptation to stressful experience. Here, we therefore investigated the interaction between Cdh13 variation and neonatal maternal separation (MS) in mice.

METHODS

Male and female wild-type (Cdh13^+/+), heterozygous (Cdh13^+/-) and homozygous (Cdh13^-/-) knockout mice exposed to MS, or daily handling as control, were subjected to a battery of behavioural tests to assess motor activity, learning and memory as well as anxiety-like behaviour. A transcriptome analysis of the hippocampus was performed in an independent cohort of mice which was exposed to MS or handling, but remained naïve for behavioural testing.

RESULTS

MS lead to increased anxiety-like behaviour in Cdh13^-/- mice compared to the other two MS groups. Cdh13^-/- mice showed a context-dependent effect on stress- and anxiety-related behaviour, impaired extinction learning following contextual fear conditioning and decreased impulsivity, as well as a mild decrease in errors in the Barnes maze and reduced risk-taking in the light-dark transition test after MS. We also show sex differences, with increased locomotor activity in female Cdh13^-/- mice, but unaltered impulsivity and activity in male Cdh13^-/- mice. Transcriptome analysis revealed several pathways associated with cell surface/adhesion molecules to be altered following Cdh13 deficiency, together with an influence on endoplasmic reticulum function.

CONCLUSION

MS resulted in increased stress resilience, increased exploration and an overall anxiolytic behavioural phenotype in male Cdh13^+/+ and Cdh13^+/- mice. Cdh13 deficiency, however, obliterated most of the effects caused by early-life stress, with Cdh13^-/- mice exhibiting delayed habituation, no reduction of anxiety-like behaviour and decreased fear extinction. Our behavioural findings indicate a role of CDH13 in the programming of and adaptation to early-life stress. Finally, our transcriptomic data support the view of CDH13 as a neuroprotective factor as well as a mediator in cell-cell interactions, with an impact on synaptic plasticity.

Dissociation of impulsivity and aggression in mice deficient for the ADHD risk gene Adgrl3: Evidence for dopamine transporter dysregulation

Adhesion G protein-coupled receptor L3 (ADGRL3, LPHN3) has putative roles in neuronal migration and synapse function. Various polymorphisms in ADGRL3 have been linked with an increased risk of attention deficit/hyperactivity disorder (ADHD). In this study, we examined the characteristics of Adgrl3-deficient mice in multiple behavioural domains related to ADHD: locomotive activity, impulsivity, gait, visuospatial and recognition memory, sociability, anxiety-like behaviour and aggression. Additionally, we investigated the effect of Adgrl3-depletion at the transcriptomic level by RNA-sequencing three ADHD-relevant brain regions: prefrontal cortex (PFC), hippocampus and striatum. Adgrl3^-/- mice show increased locomotive activity across all tests and subtle gait abnormalities. These mice also show impairments across spatial memory and learning domains, alongside increased levels of impulsivity and sociability with decreased aggression. However, these alterations were absent in Adgrl3^+/- mice. Across all brain regions tested, the numbers of genes found to exhibit differential expression was relatively small, indicating a specific pathway of action, rather than a broad neurobiological perturbation. Gene-set analysis of differential expression in the PFC detected a number of ADHD-relevant pathways including dopaminergic synapses as well as cocaine and amphetamine addiction. The Slc6a3 gene coding for the dopamine transporter was the most dysregulated gene in the PFC. Unexpectedly, several neurohormone/peptides which are typically only expressed in the hypothamalus were found to be dysregulated in the striatum. Our study further validates Adgrl3 constitutive knockout mice as an experimental model of ADHD while providing neuroanatomical targets for future studies involving ADGRL3 modified models. This article is part of the Special Issue entitled 'Current status of the neurobiology of aggression and impulsivity'.

Analysis of shared heritability in common disorders of the brain

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.

Cadherin-13 Deficiency Increases Dorsal Raphe 5-HT Neuron Density and Prefrontal Cortex Innervation in the Mouse Brain

Background: During early prenatal stages of brain development, serotonin (5-HT)-specific neurons migrate through somal translocation to form the raphe nuclei and subsequently begin to project to their target regions. The rostral cluster of cells, comprising the median and dorsal raphe (DR), innervates anterior regions of the brain, including the prefrontal cortex. Differential analysis of the mouse 5-HT system transcriptome identified enrichment of cell adhesion molecules in 5-HT neurons of the DR. One of these molecules, cadherin-13 (Cdh13) has been shown to play a role in cell migration, axon pathfinding, and synaptogenesis. This study aimed to investigate the contribution of Cdh13 to the development of the murine brain 5-HT system.

Methods: For detection of Cdh13 and components of the 5-HT system at different embryonic developmental stages of the mouse brain, we employed immunofluorescence protocols and imaging techniques, including epifluorescence, confocal and structured illumination microscopy. The consequence of CDH13 loss-of-function mutations on brain 5-HT system development was explored in a mouse model of Cdh13 deficiency.

Results: Our data show that in murine embryonic brain Cdh13 is strongly expressed on 5-HT specific neurons of the DR and in radial glial cells (RGCs), which are critically involved in regulation of neuronal migration. We observed that 5-HT neurons are intertwined with these RGCs, suggesting that these neurons undergo RGC-guided migration. Cdh13 is present at points of intersection between these two cell types. Compared to wildtype controls, Cdh13-deficient mice display increased cell densities in the DR at embryonic stages E13.5, E17.5, and adulthood, and higher serotonergic innervation of the prefrontal cortex at E17.5.

Conclusion: Our findings provide evidence for a role of CDH13 in the development of the serotonergic system in early embryonic stages. Specifically, we indicate that Cdh13 deficiency affects the cell density of the developing DR and the posterior innervation of the prefrontal cortex (PFC), and therefore might be involved in the migration, axonal outgrowth and terminal target finding of DR 5-HT neurons. Dysregulation of CDH13 expression may thus contribute to alterations in this system of neurotransmission, impacting cognitive function, which is frequently impaired in neurodevelopmental disorders including attention-deficit/hyperactivity and autism spectrum disorders.

Genome-wide analyses of aggressiveness in attention-deficit hyperactivity disorder

Aggressiveness is a behavioral trait that has the potential to be harmful to individuals and society. With an estimated heritability of about 40%, genetics is important in its development. We performed an exploratory genome-wide association (GWA) analysis of childhood aggressiveness in attention deficit hyperactivity disorder (ADHD) to gain insight into the underlying biological processes associated with this trait. Our primary sample consisted of 1,060 adult ADHD patients (aADHD). To further explore the genetic architecture of childhood aggressiveness, we performed enrichment analyses of suggestive genome-wide associations observed in aADHD among GWA signals of dimensions of oppositionality (defiant/vindictive and irritable dimensions) in childhood ADHD (cADHD). No single polymorphism reached genome-wide significance (P < 5.00E-08). The strongest signal in aADHD was observed at rs10826548, within a long noncoding RNA gene (beta = -1.66, standard error (SE) = 0.34, P = 1.07E-06), closely followed by rs35974940 in the neurotrimin gene (beta = 3.23, SE = 0.67, P = 1.26E-06). The top GWA SNPs observed in aADHD showed significant enrichment of signals from both the defiant/vindictive dimension (Fisher's P-value = 2.28E-06) and the irritable dimension in cADHD (Fisher's P-value = 0.0061). In sum, our results identify a number of biologically interesting markers possibly underlying childhood aggressiveness and provide targets for further genetic exploration of aggressiveness across psychiatric disorders. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.

Annual research review: The (epi)genetics of neurodevelopmental disorders in the era of whole-genome sequencing--unveiling the dark matter

BACKGROUND AND SCOPE

Neurodevelopmental disorders (NDDs) are defined by a wide variety of behavioural phenotypes, psychopathology and clinically informed categorical classifications. Diagnostic entities include intellectual disability (ID), the autism spectrum (ASD) and attention-deficit/hyperactivity disorder (ADHD). The aetiopathogenesis of these conditions and disorders involves an interaction between both genetic and environmental risk factors on the developmental trajectory. Despite their remarkable genetic heterogeneity and complexity of pathophysiological mechanisms, NDDs display an overlap in their phenotypic features, a considerable degree of comorbidity as well as sharing of genetic and environmental risk factors. This review aims to provide an overview of the genetics and epigenetic of NDDs.

FINDINGS

Recent evidence suggests a critical role of defined and tightly regulated neurodevelopmental programs running out of control in NDDs, most notably neuronal proliferation and migration, synapse formation and remodelling, as well as neural network configuration resulting in compromised systems connectivity and function. Moreover, the machinery of epigenetic programming, interacting with genetic liability, impacts many of those processes and pathways, thus modifying vulnerability of, and resilience to, NDDs. Consequently, the categorically defined entities of ID, ADHD and ASD are increasingly viewed as disorders on a multidimensional continuum of molecular and cellular deficiencies in neurodevelopment. As such, this range of NDDs displays a broad phenotypic diversity, which may be explained by a combination and interplay of underlying loss- and potential gain-of-function traits.

CONCLUSION

In this overview, we discuss a backbone continuum concept of NDDs by summarizing pertinent findings in genetics and epigenetics. We also provide an appraisal of the genetic overlap versus differences, with a focus on genome-wide screening approaches for (epi)genetic variation. Finally, we conclude with insights from evolutionary psychobiology suggesting positive selection for discrete NDD-associated traits.

Replication of previous genome-wide association studies of psychiatric diseases in a large schizophrenia case-control sample from Spain

Genome wide association studies (GWAS) has allowed the discovery of some interesting risk variants for schizophrenia (SCZ). However, this high-throughput approach presents some limitations, being the most important the necessity of highly restrictive statistical corrections as well as the loss of statistical power inherent to the use of a Single Nucleotide Polymorphism (SNP) analysis approach. These problems can be partially solved through the use of a polygenic approach. We performed a genotyping study in SCZ using 86 previously associated SNPs identified by GWAS of SCZ, bipolar disorder (BPD) and autistic spectrum disorder (ASD) patients. The sample consisted of 3063 independent cases with DSM-IV-TR diagnosis of SCZ and 2847 independent controls of European origin from Spain. A polygenic score analysis was also used to test the overall effect on the SCZ status. One SNP, rs12290811, located in the ODZ4 gene reached statistical significance (p=1.7×10(-4), Allelic odds ratio=1.21), a value very near to those reported in previous GWAS of BPD patients. In addition, 4 SNPs were close to the significant threshold: rs3850333, in the NRXN1 gene; rs6932590, at MHC; rs2314398, located in an intergenic region on chromosome 2; and rs1006737, in the CACNA1C gene. We also found that 74% of the studied SNPs showed the same tendency (risk or protection alleles) previously reported in the original GWAS (p<0.001). Our data strengthen the polygenic component of susceptibility to SCZ. Our findings show ODZ4 as a risk gene for SCZ, emphasizing the existence of common vulnerability in psychosis.

The genetic contribution of the NO system at the glutamatergic post-synapse to schizophrenia: further evidence and meta-analysis

NO is a pleiotropic signaling molecule and has an important role in cognition and emotion. In the brain, NO is produced by neuronal nitric oxide synthase (NOS-I, encoded by NOS1) coupled to the NMDA receptor via PDZ interactions; this protein-protein interaction is disrupted upon binding of NOS1 adapter protein (encoded by NOS1AP) to NOS-I. As both NOS1 and NOS1AP were associated with schizophrenia, we here investigated these genes in greater detail by genotyping new samples and conducting a meta-analysis of our own and published data. In doing so, we confirmed association of both genes with schizophrenia and found evidence for their interaction in increasing risk towards disease. Our strongest finding was the NOS1 promoter SNP rs41279104, yielding an odds ratio of 1.29 in the meta-analysis. As findings from heterologous cell systems have suggested that the risk allele decreases gene expression, we studied the effect of the variant on NOS1 expression in human post-mortem brain samples and found that the risk allele significantly decreases expression of NOS1 in the prefrontal cortex. Bioinformatic analyses suggest that this might be due the replacement of six transcription factor binding sites by two new binding sites as a consequence of proxy SNPs. Taken together, our data argue that genetic variance in NOS1 resulting in lower prefrontal brain expression of this gene contributes to schizophrenia liability, and that NOS1 interacts with NOS1AP in doing so. The NOS1-NOS1AP PDZ interface may thus well constitute a novel target for small molecules in at least some forms of schizophrenia.

Association study of nonsynonymous single nucleotide polymorphisms in schizophrenia

BACKGROUND

Genome-wide association studies using several hundred thousand anonymous markers present limited statistical power. Alternatively, association studies restricted to common nonsynonymous single nucleotide polymorphisms (nsSNPs) have the advantage of strongly reducing the multiple testing problem, while increasing the probability of testing functional single nucleotide polymorphisms (SNPs).

METHODS

We performed a case-control association study of common nsSNPs in Galician (northwest Spain) samples using the Affymetrix GeneChip Human 20k cSNP Kit, followed by a replication study of the more promising results. After quality control procedures, the discovery sample consisted of 5100 nsSNPs at minor allele frequency >5% analyzed in 476 schizophrenia patients and 447 control subjects. The replication sample consisted of 4069 cases and 15,128 control subjects of European origin. We also performed multilocus analysis, using aggregated scores of nsSNPs at liberal significance thresholds and cross-validation procedures.

RESULTS

The 5 independent nsSNPs with false discovery rate q ≤ .25, as well as 13 additional nsSNPs at p < .01 and located in functional candidate genes, were genotyped in the replication samples. One SNP, rs13107325, located at the metal ions transporter gene SLC39A8, reached significance in the combined sample after Bonferroni correction (trend test, p = 2.7 × 10(-6), allelic odds ratio = 1.32). This SNP presents minor allele frequency of 5% to 10% in many European populations but is rare outside Europe. We also confirmed the polygenic component of susceptibility.

CONCLUSIONS

Taking into account that another metal ions transporter gene, SLC39A3, is associated to bipolar disorder, our findings reveal a role for brain metal homeostasis in psychosis.

Impact of the AHI1 gene on the vulnerability to schizophrenia: a case-control association study

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<p<0.036). Joint analysis also supported the association of rs7750586 and rs911507 with the risk for schizophrenia. The analysis of clinical measures also revealed an effect on symptom severity (minimum P value = 0.0037).

Conclusions/Significance

Our data support, in agreement with previous reports, an effect of AHI1 variation on the susceptibility to schizophrenia in central and southern European populations.

Molecular Cloning of the Tryptophan Operon from an Aeromonas hydrophila Freshwater Isolate

A genomic library of Aeromonas hydrophila F9 was constructed by using pBR322 as a vector. From that, two DNA fragments (5.8 and 11.6 kb) were isolated containing genetic information to complement trpA and trpB defects (5.8-kb fragment) and to complement trpA, trpB, trpC, trpD, and trpE defects (11.6-kb fragment) in Escherichia coli mutants. Evidence of the existence of a secondary promoter is given.

Serotonin transporter gene polymorphisms and auditory hallucinations in psychosis

INTRODUCTION

To study the role of the serotonin transporter gene (SLC6A4) in the emotional processing of auditory hallucinations can be particularly important to better understand the pathophysiology of auditory hallucinations. Moreover, a poly-morphism located in this gene (5-HTTLPR) has been previously associated with different disorders related to altered emotional responses. The aim of this study was to evaluate the relationship between different polymorphisms of the SLC6A4 gene and different aspects of auditory hallucinations in schizophrenic patients, with a special consideration toward the emotional response to auditory hallucinations.

SUBJECTS AND METHODS

Two samples of 224 patients with auditory hallucinations and 346 healthy subjects were studied. AH were assessed in patients through the PSYRATS scale for auditory hallucinations. Several polymorphisms located within the SLC6A4 gene were analysed through case-control comparisons as well as association analyses with different parameters of auditory hallucinations.

RESULTS

No differences were found between patients and controls for any of the analysed polymorphisms (p > 0.05). However, the evaluation of auditory hallucinations parameters showed that the low expressing alleles of the 5-HTTLPR polymorphism were associated with higher levels of intensity of the distress caused by auditory hallucinations (p = 0.049 corrected for the item 'intensity of distress'). There was also a trend with the parameter disruption (p = 0.06 corrected). These two items of the PSYRATS scale are directly related to the emotional dimension of auditory hallucinations. In contrast, we did not observe any association with items related to other dimensions of auditory hallucinations.

CONCLUSIONS

Our results support a possible role of the serotonin transporter in the emotional response to auditory hallucinations.

El colgajo romboidal de Limberg en el tratamiento del quiste mucoide

Objetivo: Valorar los resultados obtenidos mediante el colgajo romboidal de Limberg en pacientes con quiste mucoide.

Material y Método: Se analizan un total de 30 pacientes (18 mujeres, 12 hombres) con quiste mucoide situado en el dorso de la articulación interfalángica distal. En todos los casos el tratamiento fue el mismo, mediante la resección en bloque del quiste y piel suprayacente, y cubrimiento del defecto mediante colgajo romboidal de Limberg. El seguimiento mínimo de estos pacientes fue de 13 meses, con un mínimo de 6 meses y un máximo de 32 meses.

Resultados: Todos los pacientes estuvieron satisfechos con el resultado cosmético conseguido. No hubo que lamentar ningún caso de recidiva, infección ni de necrosis cutánea.

Conclusiones: Dentro de las opciones quirúrgicas existentes para el tratamiento del quiste mucoide, creemos que el colgajo romboidal de Limberg, por su sencillez, resolución y aspecto estético, constituye una alternativa válida en este tipo de patologías.

Association between CCK-AR gene and schizophrenia with auditory hallucinations

OBJECTIVE

Previous studies on a possible association between CCK-AR polymorphisms and schizophrenia have been controversial. The aim of the present study was to assess a potential association between schizophrenic patients with auditory hallucinations and polymorphisms of the CCK-AR gene.

METHODS

A set of single nucleotide polymorphisms mainly located in the regulatory region of the CCK-AR gene was analysed in a sample of 163 Diagnostic and statistical manual of mental disorders-IV-diagnosed schizophrenic patients and 162 healthy controls.

RESULTS

Significant differences in the genotype (P=0.011) and allele (P=0.0009) frequencies of the +121C/G SNP (located in the 5' regulatory region) were found between patients and controls. The excess of the C allele in the patient group remained significant after Bonferroni correction (P=0.03). However, functional in vitro assays, did not reveal significant differences on gene expression between +121G and +121C alleles of this SNP. Further investigations revealed two risk haplotypes: +121C/+978A/+984T (P=0.01) and +121C/+978T/+984C (P=0.0091) as well as a protective haplotype: +121G/+978T/+984T (P=0.0001).

CONCLUSION

Our data support a possible role of the CCK-AR gene in the vulnerability to schizophrenia in patients with auditory hallucinations, and suggest remarkable allele heterogeneity.

[Prostatic adenocarcinoma with neuroendocrine differentiation of the small cell type]

Adenocarcinomas (AC) account for more than 90% of the prostatic malignant neoplasias; a neuroendocrine differentiation (NE) component is to be considered in cases of atypical evolution for its diagnostic and therapeutic relevance. The (NE) originates by proliferation of the NE cells of the acinar epithelium and may develop into two different histologic patterns, a "Carcinoid" type and a "Small Cell" type. We report a patient with a prostatic AC diagnosed 5 years before his death with worsening of the disease together with a return of the prostatic specific antigen (PSA) to normal values and the presence of hepatic metastases of a tumor (NE) of the small cell type. The autopsy confirmed the presence of a prostatic tumor with areas of (AC) type and (NE) small cell type and multiple hepatic metastases (NE).

Bronchogenic cancer in patients under 40 years old. The experience of a Latin American country

Lung cancer in young patients is increasing in frequency, as documented by data from the United States, Canada, Japan, and European countries. However, to date and to our knowledge, there have not been any reports from Latin America on this topic. The published reports show that lung cancer in young patients is associated with smoking habit and family history of lung cancer. Its clinical course seems to be more aggressive than in older patients and the histologic type is less often squamous type. We describe 48 patients, aged 40 years or younger, who were diagnosed as having lung cancer in the Instituto Nacional de Cancerología from 1980 to 1990. The patients were equally divided between men and women. Smoking was documented for only 46 percent of the cases. The histologic type most frequently diagnosed was adenocarcinoma (N = 26) followed by squamous cell carcinoma (N = 12). Almost all the cases (46 cases) were staged IV according to the TNM classification. A group of 33 patients older than 40 years (56 to 82 years) were used for comparison. The differences in sex ratio that were higher for men in the elder (m/f, 2.7:1) were family history for cancer in six patients elder; positive smoking habit in all the aged patients (100 percent) compared with only 43.7 percent in the younger group; histologic type (26 adenocarcinomas and 4 squamous in the younger compared with 14 and 12, respectively, in the elder).

Comparative study of virulence and virulence factors of Aeromonas hydrophila strains isolated from water and sediments of a river

Seventy-four strains of Aeromonas hydrophila isolated from water and sediments of the River Porma (León, N.W. Spain) were characterized biochemically and biologically. Fifty-seven strains (77.02%) were virulent for rainbow trout (Salmo gairdneri) by intramuscular challenge but showed differing degree of pathogenicity which could not be associated with the source. A lack of correlation between caseinase, haemolytic and cytotoxic activities of the strains and their isolation source was also observed. Only two surface characters, acriflavine 0.2% agglutination and non-agglutinating SP-/PAB-phenotypes, were significantly associated with water and sediment strains, respectively.

Cloning and characterization of an extracellular temperature-labile serine protease gene from Aeromonas hydrophila

Aeromonas virulence is thought to depend on multigenic functions. The gene for an extracellular protease from Aeromonas hydrophila SO2/2 was cloned in Escherichia coli C600-1 by using pIJ860, bifunctional plasmid, as a vector. The gene encodes for a temperature-labile serine protease (P2) with a molecular mass of approx. 68 kDa which is highly inhibited by PMSF. The gene was expressed in Streptomyces lividans 1326 by transforming protoplasts with the original clone pPA2. We were also able to transfer and express the prt P2 gene in Pseudomonas putida by mating experiments. The protein P2 was secreted into the periplasms of both P. putida and E. coli C600-1 being identical in properties to one of the proteases secreted into the culture supernatant by A. hydrophila SO2/2.

Molecular cloning and characterization of an extracellular protease gene from Aeromonas hydrophila

A structural gene which codes for an extracellular protease in Aeromonas hydrophilia SO2/2 and D13 was cloned in Escherichia coli C600-1 by using pBR322 as a vector. The gene codes for a temperature-stable protease with a molecular mass of approximately 38,000 daltons. The protein was secreted to the periplasm of E. coli C600-1 and purified by osmotic shock. Cloned protease (P3) was identical in molecular mass and properties to the one purified from A. hydrophila SO2/2 culture supernatant as an extracellular product.

Pathogenicity factors and virulence for rainbow trout (Salmo gairdneri) of motile Aeromonas spp. isolated from a river

Ninety-seven motile Aeromonas strains were isolated over a period of a year from samples of water and sediment collected at different sites along a river. Strains were regularly recovered from all samples, regardless of the source of isolation or seasonal conditions. Isolates were biochemically characterized by the API 20NE system (Analytab Products, Plainview, N.Y.) and classified as Aeromonas hydrophila (74 strains), Aeromonas sobria (11 strains), and Aeromonas caviae (12 strains). Despite the high level of homogeneity observed in their biochemical patterns, they displayed different degrees of virulence for fish; 72.02% of A. hydrophila isolates and 63% of A. sobria isolates were virulent for fish by intramuscular challenge, but lower frequencies of virulence were observed when intraperitoneal injections were used. All A. caviae strains proved to be avirulent. Caseinases, hemolysins, and Vero cytotoxins were produced by 100, 91, and 94.59%, respectively, of A. hydrophila strains and with lower frequencies and lower caseinase activities by A. sobria isolates. No correlation was found between these activities and the degree of virulence of the strains for fish. Most hydrophobic strains seem to be concentrated in A. caviae, A. sobria, and avirulent A. hydrophila groups. Known virulence markers commonly associated with virulent strains (acriflavine negative and self-pelleting negative and precipitation after boiling positive phenotypes) had a low representation in the total of strains studied and were not associated with virulence.

Lymphatics of the diaphragm in the dog

Lymphography of the diaphragm was performed in 35 dogs. A main diaphragmatic duct passed in a postero-anterior direction, receiving several branches from the diaphragm. It passed to a double mammary internal channel ending at the upper end of the sternum, where a group of nodes were constantly present, and beyond this a lymphatic plexus was filled.