Testing allele homogeneity: the problem of nested hypotheses.

BACKGROUND: The evaluation of associations between genotypes and diseases in a case-control framework plays an important role in genetic epidemiology. This paper focuses on the evaluation of the homogeneity of both genotypic and allelic frequencies. The traditional test that is used to check allelic homogeneity is known to be valid only under Hardy-Weinberg equilibrium, a property that may not hold in practice. RESULTS: We first describe the flaws of the traditional (chi-squared) tests for both allelic and genotypic homogeneity. Besides the known problem of the allelic procedure, we show that whenever these tests are used, an incoherence may arise: sometimes the genotypic homogeneity hypothesis is not rejected, but the allelic hypothesis is. As we argue, this is logically impossible. Some methods that were recently proposed implicitly rely on the idea that this does not happen. In an attempt to correct this incoherence, we describe an alternative frequentist approach that is appropriate even when Hardy-Weinberg equilibrium does not hold. It is then shown that the problem remains and is intrinsic of frequentist procedures. Finally, we introduce the Full Bayesian Significance Test to test both hypotheses and prove that the incoherence cannot happen with these new tests. To illustrate this, all five tests are applied to real and simulated datasets. Using the celebrated power analysis, we show that the Bayesian method is comparable to the frequentist one and has the advantage of being coherent. CONCLUSIONS: Contrary to more traditional approaches, the Full Bayesian Significance Test for association studies provides a simple, coherent and powerful tool for detecting associations.

Sensory phenomena associated with repetitive behaviors in obsessive-compulsive disorder: an exploratory study of 1001 patients.

A substantial number of patients with obsessive-compulsive disorder (OCD) report compulsions that are preceded not by obsessions but by subjective experiences known as sensory phenomena. This study aimed to investigate the frequency, severity, and age at onset of sensory phenomena in OCD, as well as to compare OCD patients with and without sensory phenomena in terms of clinical characteristics. We assessed 1,001 consecutive OCD patients, using instruments designed to evaluate the frequency/severity of OC symptoms, tics, anxiety, depression, level of insight and presence/severity of sensory phenomena. All together, 651 (65.0%) subjects reported at least one type of sensory phenomena preceding the repetitive behaviors. Considering the sensory phenomena subtypes, 371 (57.0%) patients had musculoskeletal sensations, 519 (79.7%) had externally triggered "just-right" perceptions, 176 (27.0%) presented internally triggered "just right," 144 (22.1%) had an "energy release," and 240 (36.9%) patients had an "urge only" phenomenon. Sensory phenomena were described as being as more severe than were obsessions by 102(15.7%) patients. Logistic regression analysis showed that the following characteristics were associated with the presence of sensory phenomena: higher frequency and greater severity of the symmetry/ordering/arranging and contamination/washing symptom dimensions; comorbid Tourette syndrome, and a family history of tic disorders. These data suggest that sensory phenomena constitute a poorly understood psychopathological aspect of OCD that merits further investigation.

Clinical features of tic-related obsessive-compulsive disorder: results from a large multicenter study.

OBJECTIVE: To evaluate the clinical features of obsessive-compulsive disorder (OCD) patients with comorbid tic disorders (TD) in a large, multicenter, clinical sample. METHOD: A cross-sectional study was conducted that included 813 consecutive OCD outpatients from the Brazilian OCD Research Consortium and used several instruments of assessment, including the Yale-Brown Obsessive-Compulsive Scale, the Dimensional Yale-Brown Obsessive-Compulsive Scale, the Yale Global Tic Severity Scale (YGTSS), the USP Sensory Phenomena Scale, and the Structured Clinical Interview for DSM-IV Axis I Disorders. RESULTS: The sample mean current age was 34.9 years old (SE 0.54), and the mean age at obsessive-compulsive symptoms (OCS) onset was 12.8 years old (SE 0.27). Sensory phenomena were reported by 585 individuals (72% of the sample). The general lifetime prevalence of TD was 29.0% (n = 236), with 8.9% (n = 72) presenting Tourette syndrome, 17.3% (n = 141) chronic motor tic disorder, and 2.8% (n = 23) chronic vocal tic disorder. The mean tic severity score, according to the YGTSS, was 27.2 (SE 1.4) in the OCD + TD group. Compared to OCD patients without comorbid TD, those with TD (OCD + TD group, n = 236) were more likely to be males (49.2% vs. 38.5%, p < .005) and to present sensory phenomena and comorbidity with anxiety disorders in general: separation anxiety disorder, social phobia, specific phobia, generalized anxiety disorder, post-traumatic stress disorder, attention-deficit hyperactivity disorder, impulse control disorders in general, and skin picking. Also, the "aggressive," "sexual/religious," and "hoarding" symptom dimensions were more severe in the OCD + TD group. CONCLUSION: Tic-related OCD may constitute a particular subgroup of the disorder with specific phenotypical characteristics, but its neurobiological underpinnings remain to be fully disentangled.

Body dysmorphic disorder among dermatologic patients: Prevalence and clinical features.

BACKGROUND: An impairing preoccupation with a nonexistent or slight defect in appearance is the core symptom of body dysmorphic disorder (BDD), a psychiatric condition common in dermatology settings. OBJECTIVE: We sought to determine the prevalence of BDD in dermatologic patients, comparing general and cosmetic settings, and describing some demographic and clinical characteristics. METHODS: In all, 300 patients were consecutively assessed. Screening and diagnoses were performed with validated instruments plus a best estimate diagnosis procedure. The final sample comprised 150 patients in the cosmetic group, 150 patients in the general dermatology group, and 50 control subjects. Standard statistical analyses were performed (chi(2), nonparametric tests, logistic regression). RESULTS: The current prevalence was higher in the cosmetic group (14.0%) compared with general (6.7%) and control (2.0%) groups. No patient had a previous diagnosis. Frequently the reason for seeking dermatologic treatment was not the main BDD preoccupation. Patients with BDD from the cosmetic group were in general unsatisfied with the results of dermatologic treatments. LIMITATIONS: Cross-sectional study conducted in a university hospital is a limitation. It is uncertain if the findings can be generalized. Retrospective data regarding previous treatments are not free from bias. CONCLUSIONS: BDD is relatively common in a dermatologic setting, especially among patients seeking cosmetic treatments. These patients have some different features compared with general dermatology patients. Dermatologists should be aware of the clinical characteristics of BDD to identify and refer these patients to mental health professionals.

Validation of the University of São Paulo Sensory Phenomena Scale: initial psychometric properties.

INTRODUCTION: Although obsessions and compulsions comprise the main features of obsessive-compulsive disorder (OCD), many patients report that their compulsions are preceded by a sense of "incompleteness" or other unpleasant feelings such as premonitory urges or a need perform actions until feeling "just right." These manifestations have been characterized as Sensory Phenomena (SP). The current study presents initial psychometric data for a new scale designed to measure SP. METHODS: Seventy-six adult OCD subjects were probed twice. Patients were assessed with an open clinical interview (considered as the "gold standard") and with the following standardized instruments: Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders, Yale-Brown Obsessive-Compulsive Scale, Dimensional Yale-Brown Obsessive-Compulsive Scale, Yale Global Tic Severity Scale, Beck Anxiety Inventory, and Beck Depression Inventory. RESULTS: SP were present in 51 OCD patients (67.1%). Tics were present in 16 (21.1%) of the overall sample. The presence of SP was significantly higher in early-onset OCD patients. There were no significant differences in the presence of SP according to comorbidity with tics or gender. The comparison between the results from the open clinical interviews and the University of São Paulo Sensory Phenomena Scale (USP-SPS) showed an excellent concordance between them, with no significant differences between interviewers. The inter-rater reliability between the expert raters for the USP-SPS was high, with K=.92. The Pearson correlation coefficient between the SP severity scores given by the two raters was .89. CONCLUSION: Preliminary results suggest that the USP-SPS is a valid and reliable instrument for assessing the presence and severity of SP in OCD subjects.

Association study between the -62A/T NFKBIL1 polymorphism and obsessive-compulsive disorder.

OBJECTIVE: Evidence from family and molecular genetic studies support the hypothesis of involvement of immunologic mechanisms in the pathophysiology of obsessive-compulsive disorder. The nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-like 1 (NFKBIL1) has been suggested as a modulator of the immunological system. Given the importance of NFKBIL1 in the immunological response, the present study investigated the -62A/T polymorphism (rs2071592), located in the promoter region of its gene (NFKBIL1), as a genetic risk factor for the development of obsessive-compulsive disorder. METHOD: The -62A/T NFKBIL1 polymorphism was investigated in a sample of 111 patients who met DSM-IV criteria for obsessive-compulsive disorder and 272 healthy age- and gender-matched controls. RESULTS: There were no differences in genotypic distributions between patients and controls (chi2 = 0.98; 2 d.f.; p = 0.61). DISCUSSION: Despite these negative findings, more comprehensive polymorphism coverage within the NFKBIL1 is warranted in larger samples. Populations with different ethnic backgrounds should also be studied. CONCLUSION: The results of the present investigation do not provide evidence for the association between the -62A/T NFKBIL1 polymorphism and obsessive-compulsive disorder in this Brazilian sample.

Neurological Improvement with Medical Cannabis in a Progressive Supranuclear Palsy Patient: A Case Report.

Progressive supranuclear palsy (PSP) is a severe, debilitating, and often fatal disease resembling other neurodegenerative disorders, namely Alzheimer's (AD) and Parkinson's (PD) diseases, which have been successfully treated with cannabinoids. We herein report the case of a 71-year-old woman diagnosed with PSP, displaying severe impairment of motor and language functions which progressively improved after treatment with medical cannabis. Before treatment, the patient was unable to move her limbs, was fed soft food, and was unable to speak or move her eyes. The patient has regained horizontal eye movement, is able to walk with assistance, has returned to physiotherapy, started to eat solid food, and has had a remarkable improvement in her speech. The possible mechanisms of this improvement are discussed.

TNF-alpha polymorphisms are associated with obsessive-compulsive disorder.

INTRODUCTION: Several lines of evidence support an immunologic involvement in obsessive-compulsive disorder (OCD): the increased prevalence of OCD in patients with rheumatic fever (RF), and the aggregation of obsessive-compulsive spectrum disorders among relatives of RF probands. Tumor necrosis factor alpha is a proinflammatory cytokine involved in RF and other autoimmune diseases. Polymorphisms in the promoter region of the TNFA gene have been associated with RF. Given the association between OCD and RF, the goal of the present study was to investigate a possible association between polymorphisms within the promoter region of TNFA and OCD. MATERIALS AND METHODS: Two polymorphisms were investigated: -308 G/A and -238 G/A. The allelic and genotypic frequencies of these polymorphisms were examined in 111 patients who fulfilled DSM-IV criteria for OCD and compared with the frequencies in 250 controls. RESULTS: Significant associations were observed between both polymorphisms and OCD. For -238 G/A, an association between the A allele and OCD was observed (chi(2)=12.05, p=0.0005). A significant association was also observed between the A allele of the -308 G/A polymorphism and OCD (chi(2)=7.09, p=0.007). Finally, a haplotype consisting of genotypes of these two markers was also examined. Significant association was observed for the A-A haplotype (p=0.0099 after correcting for multiple testing). DISCUSSION: There is association between the -308 G/A and -238 G/A TNFA polymorphisms and OCD in our Brazilian sample. However, these results need to be replicated in larger samples collected from different populations.

The Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders: recruitment, assessment instruments, methods for the development of multicenter collaborative studies and preliminary results.

OBJECTIVE: To describe the recruitment of patients, assessment instruments, implementation, methods and preliminary results of The Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders, which includes seven university sites. METHOD: This cross-sectional study included a comprehensive clinical assessment including semi-structured interviews (sociodemographic data, medical and psychiatric history, disease course and comorbid psychiatric diagnoses), and instruments to assess obsessive-compulsive (Yale-Brown Obsessive-Compulsive Scale and Dimensional Yale-Brown Obsessive-Compulsive Scale), depressive (Beck Depression Inventory) and anxious (Beck Anxiety Inventory) symptoms, sensory phenomena (Universidade de São Paulo Sensory Phenomena Scale), insight (Brown Assessment Beliefs Scale), tics (Yale Global Tics Severity Scale) and quality of life (Medical Outcome Quality of Life Scale Short-form-36 and Social Assessment Scale). The raters' training consisted of watching at least five videotaped interviews and interviewing five patients with an expert researcher before interviewing patients alone. The reliability between all leaders for the most important instruments (Structured Clinical Interview for DSM-IV, Dimensional Yale-Brown Obsessive-Compulsive Scale, Universidade de São Paulo Sensory Phenomena Scale) was measured after six complete interviews. RESULTS: Inter-rater reliability was 96%. By March 2008, 630 obsessive-compulsive disorder patients had been systematically evaluated. Mean age (+/-SE) was 34.7 (+/-0.51), 56.3% were female, and 84.6% Caucasian. The most prevalent obsessive compulsive symptom dimensions were symmetry and contamination. The most common comorbidities were major depression, generalized anxiety and social anxiety disorder. The most common DSM-IV impulsive control disorder was skin picking. CONCLUSION: The sample was composed mainly by Caucasian individuals, unmarried, with some kind of occupational activity, mean age of 35 years, onset of obsessive-compulsive symptoms at 13 years of age, mild to moderate severity, mostly of symmetry, contamination/cleaning and comorbidity with depressive disorders. The Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders has established an important network for standardized collaborative clinical research in obsessive-compulsive disorder and may pave the way to similar projects aimed at integrating other research groups in Brazil and throughout the world.

Prenatal, perinatal, and postnatal risk factors in obsessive-compulsive disorder.

BACKGROUND: The etiology of obsessive-compulsive disorder (OCD) remains unknown, although it is thought to involve an interaction of genetic and environmental factors. This study aimed to identify prenatal, perinatal, and postnatal risk factors in OCD. METHODS: We compared retrospectively 68 OCD patients to 70 control subjects based on responses given on a standardized questionnaire. The questionnaire was designed to evaluate environmental factors, with a special focus on gestation, labor, birth, and early infancy aspects. RESULTS: The group of OCD patients had risk factors with greater frequency than the control group. Notable among the significant findings (p < or = 0.001) were edema of the hands, feet, or face and excessive weight gain during gestation; hyperemesis gravidarum; prolonged labor; preterm birth; and jaundice. When socioeconomic class was used as a covariable in the logistic regression analysis, prolonged labor and edema during pregnancy remained statistically significant. CONCLUSIONS: Some early risk factors may be associated with the expression of OCD later in life such as edema during pregnancy and prolonged labor. If our findings are confirmed in future studies, greater attention should be given to such factors in predisposed individuals, especially in prenatal care and delivery.

Obsessive-compulsive spectrum disorders and rheumatic fever: a family study.

BACKGROUND: Obsessive-compulsive spectrum disorders (OCSDs) are more frequent in patients with active or prior rheumatic fever (RF), suggesting that OCSD and RF may share underlying etiologic mechanisms. Our objective was to estimate the frequency of OCSD in first-degree relatives (FDRs) of RF patients and controls to determine whether there is a familial relationship between OCSD and RF. METHODS: This is a case-control family study. Of the 98 probands included in this study, 31 had RF without Sydenham's chorea (SC) and had 131 relatives, 28 had RF with SC and had 120 relatives, and 39 were controls without RF. All probands, 87.9% of the RF FDRs and 93.7% of the control FDRs were assessed directly with structured psychiatric interviews and best-estimate diagnoses were assigned. Odds ratios of morbid risks were estimated using logistic regression by the generalized estimating equations (GEE) method and compared between groups. RESULTS: The rate of OCSDs was significantly higher among FDRs of RF probands than among FDRs of controls (n=37; 14.7% vs. n=10; 7.3%, i=.0279). A diagnosis of OCSDs in an RF proband was associated with a higher rate of OCSDs among FDRs when compared to control FDRs (p-GEE=.02). There was a trend for a higher rate of OCSDs among FDRs of RF probands presenting no OCSD, although the difference was not significant (p-GEE=.09). CONCLUSION: The results are consistent with the hypothesis that a familial relationship exists between OCSD and RF, since an OCSD in the RF proband was found to increase the risk of OCSDs among FDRs. Additional neuroimmunological and genetic studies involving larger samples are needed to further elucidate this apparent familial relationship between RF and OCSD.

Chronic tics and Tourette syndrome in patients with obsessive-compulsive disorder.

Tourette syndrome (TS) and chronic motor/vocal tics (CMVT) are both common disorders in patients with obsessive compulsive disorder (OCD). However, there have been few studies evaluating the differences between the OCD with TS and OCD with CMVT subgroups. This study was conducted in order to further investigate possible differences between the expression of the OCD phenotype in OCD with TS and that seen in OCD with CMVT. One hundred and fifty-nine outpatients referred to an OCD research program were evaluated using the following instruments: the Structured Clinical Interview for DSM-IV; the Yale-Brown Obsessive Compulsive Scale; the Yale Global Tic Severity Scale; and the USP-HARVARD Repetitive Behaviors Interview. Patients were divided into three groups: OCD patients without tics (OCD-TICS, n=98), OCD patients with chronic motor or vocal tics (OCD+CMVT, n=31) and OCD patients with TS (OCD+TS, n=30). OCD+CMVT patients were similar to OCD+TS patients regarding the frequency of intrusive sounds, repeating behaviors, counting and tic-like compulsions (in both cases more frequent than in OCD-TICS patients). For age at obsessive-compulsive (OC) symptom onset, sensory phenomena score, number of comorbidities, frequency of somatic obsessions, bodily sensations and just-right perceptions, OCD+CMVT patients tended to be in between the other two groups. Our results suggest that there are qualitative and quantitative differences in the phenotypic expression of tic disorders in OCD patients, depending on whether the subject has TS or only CMVT.

Tourette's Syndrome.

This article has focused on TS, and the relationship between TS and OCD has been addressed from different perspectives. In patients who have OCD, the presence of TS seems to have some impact in the clinical manifestation of OCD symptoms. One of the main features of tic-related OCD is the frequent presence of sensory phenomena preceding the compulsions, in the absence of obsessions. Genetic epidemiologic studies provide consistent evidence for the association between TS and OCD. Although no major loci have been identified so far, family and segregation analysis studies support the assumption that genes play a major role in the etiology of TS and related disorders. Genes interact with environmental factors,which can modulate the expression of TS or OCD and determine the onset of these disorders. Neuroimaging studies suggest that the pathophysiology of TS encompasses projections of primary, secondary, and somato sensory cortex to the putamen, dorsolateral caudate nucleus, and globus pallidus,whereas the pathophysiology of OCD involves more ventral structures,such as orbitofrontal-caudate-thalamic-cortical areas. Current treatment strategies for TS include education, behavioral therapy, pharmacotherapy,and support from patients associations. Alfa-adrenergic agents such as guanfacine and clonidine are first-choice treatments for TS; typical antipsychotics are more effective but are troublesome because of their long-term side-effect profiles. For comorbid TS plus OCD, each condition should be treated with its respective first-line option. Nonetheless, for patients who have tic-related OCD who are unresponsive to monotherapy with serotonin reuptake inhibitors, augmentation of serotonin reuptake inhibitors with atypical antipsychotics may be of benefit. Despite important advances, re-search is needed to clarify further the biologic and behavioral aspects of TS and its relationship with the frequently associated conditions, with particular attention to their management and prognosis.

Methylphenidate use in children with attention deficit hyperactivity disorder.

A Brazilian Health Technology Assessment Bulletin (BRATS) article regarding scientific evidence of the efficacy and safety of methylphenidate for treating attention deficit hyperactivity disorder (ADHD) has caused much controversy about its methods. Considering the relevance of BRATS for public health in Brazil, we critically reviewed this article by remaking the BRATS search and discussing its methods and results. Two questions were answered: did BRATS include all references available in the literature? Do the conclusions reflect the reviewed articles? The results indicate that BRATS did not include all the references from the literature on this subject and also that the proposed conclusions are different from the results of the articles chosen by the BRATS authors themselves. The articles selected by the BRATS authors showed that using methylphenidate is safe and effective. However, the BRATS final conclusion does not reflect the aforementioned and should not be used to support decisions on the use of methylphenidate.

COMT and MAO-A polymorphisms and obsessive-compulsive disorder: a family-based association study.

OBJECTIVE: Obsessive-compulsive disorder (OCD) is a common and debilitating psychiatric illness. Although a genetic component contributes to its etiology, no single gene or mechanism has been identified to the OCD susceptibility. The catechol-O-methyltransferase (COMT) and monoamine oxidase A (MAO-A) genes have been investigated in previous OCD studies, but the results are still unclear. More recently, Taylor (2013) in a comprehensive meta-analysis of genetic association studies has identified COMT and MAO-A polymorphisms involved with OCD. In an effort to clarify the role of these two genes in OCD vulnerability, a family-based association investigation was performed as an alternative strategy to the classical case-control design. METHODS: Transmission disequilibrium analyses were performed after genotyping 13 single-nucleotide polymorphisms (eight in COMT and five in MAO-A) in 783 OCD trios (probands and their parents). Four different OCD phenotypes (from narrow to broad OCD definitions) and a SNP x SNP epistasis were also analyzed. RESULTS: OCD, broad and narrow phenotypes,were not associated with any of the investigated COMT and MAO-A polymorphisms. In addition, the analyses of gene-gene interaction did not show significant epistatic influences on phenotype between COMT and MAO-A. CONCLUSIONS: The findings do not support an association between DSM-IV OCD and the variants of COMT or MAO-A. However, results from this study cannot exclude the contribution of these genes in the manifestation of OCD. The evaluation of broader spectrum phenotypes could help to understand the role of these and other genes in the pathophysiology of OCD and its spectrum disorders.

Obsessive-compulsive spectrum disorders in rheumatic fever with and without Sydenham's chorea.

BACKGROUND: Recent findings suggest that acute-phase rheumatic fever (RF) patients present with higher frequencies of obsessive-compulsive disorder (OCD) and tic disorders. Until now, there have been no such studies in RF in non-acute phases. OBJECTIVE: To verify whether patients with a history of RF with or without Sydenham's chorea (SC) present with higher rates of OCD, tic disorders, and other obsessive-compulsive (OC) spectrum disorders (such as body dysmorphic disorder [BDD]) than controls. METHOD: Between February 1999 and December 2002, 59 consecutive outpatients with non-acute RF (28 with and 31 without SC) from an RF clinic and 39 controls from an orthopedics clinic were blindly assessed for OC spectrum disorders using structured interviews to assign DSM-IV diagnosis. Data were analyzed with Fisher exact and chi(2) tests to compare frequencies of disorders, and Kaplan-Meier survival analyses were used to obtain age-corrected rates. RESULTS: The age-corrected rates of tic disorders were higher in patients with RF without SC (N = 3; 14.39%) (p =.003) when compared with controls. Age-corrected rates for OC spectrum disorders (OCD, tic disorders, and BDD) combined were higher both in RF without SC (N = 4; 20.65%) and RF with SC (N = 5; 19.55%) groups than in controls (N = 1; 2.56%) (p =.048). CONCLUSIONS: RF, even in the non-acute phase, may increase the risk for some OC spectrum disorders, such as OCD, tic disorders, and BDD. These data, although preliminary, reinforce the idea that OC spectrum disorders may share common underlying pathophysiologic mechanisms and vulnerability factors with RF or that RF could trigger central nervous system late manifestations such as OC spectrum disorders.

An inherited small microdeletion at 15q13.3 in a patient with early-onset obsessive-compulsive disorder.

Copy number variations (CNVs) have been previously associated with several different neurodevelopmental psychiatric disorders, such as autism, schizophrenia, and attention deficit hyperactivity disorder (ADHD). The present study consisted of a pilot genome-wide screen for CNVs in a cohort of 16 patients with early-onset obsessive-compulsive disorder (OCD) and 12 mentally healthy individuals, using array-based comparative genomic hybridization (aCGH) on 44K arrays. A small rare paternal inherited microdeletion (∼64 kb) was identified in chromosome 15q13.3 of one male patient with very early onset OCD. The father did not have OCD. The deletion encompassed part of the FMN1 gene, which is involved with the glutamatergic system. This finding supports the hypothesis of a complex network of several genes expressed in the brain contributing for the genetic risk of OCD, and also supports the glutamatergic involvement in OCD, which has been previously reported in the literature.

Association study between functional polymorphisms in the TNF-alpha gene and obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is a prevalent psychiatric disorder of unknown etiology. However, there is some evidence that the immune system may play an important role in its pathogenesis. In the present study, two polymorphisms (rs1800795 and rs361525) in the promoter region of the cytokine tumor necrosis factor-alpha (TNFA) gene were genotyped in 183 OCD patients and in 249 healthy controls. The statistical tests were performed using the PLINK(®) software. We found that the A allele of the TNFA rs361525 polymorphism was significantly associated with OCD subjects, according to the allelic χ(2) association test (p=0.007). The presence of genetic markers, such as inflammatory cytokines genes linked to OCD, may represent additional evidence supporting the role of the immune system in its pathogenesis.

Brain derived neurotrophic factor mediated learning, fear acquisition and extinction as targets for developing novel treatments for anxiety / Aprendizado, aquisição e extinção de medo mediados pelo fator neurotrófico derivado do cérebro, como alvos para o desenvolvimento de novos tratamentos para ansiedade

ABSTRACT Anxiety and obsessive-compulsive related disorders are highly prevalent and disabling disorders for which there are still treatment gaps to be explored. Fear is a core symptom of these disorders and its learning is highly dependent on the activity of the neurotrophin brain-derived neurotrophic factor (BDNF). Should BDNF-mediated fear learning be considered a target for the development of novel treatments for anxiety and obsessive-compulsive related disorders? We review the evidence that suggests that BDNF expression is necessary for the acquisition of conditioned fear, as well as for the recall of its extinction. We describe the findings related to fear learning and genetic/epigenetic manipulation of Bdnf expression in animals and BDNF allelic variants in humans. Later, we discuss how manipulation of BDNF levels represents a promising potential treatment target that may increase the benefits of therapies that extinguish previously conditioned fear.

RESUMO Os transtornos da ansiedade e o transtorno obsessivo-compulsivo (TOC) e transtornos relacionados são altamente prevalentes e incapacitantes. Apesar disso, ainda existem lacunas a serem exploradas em relação ao tratamento desses transtornos. O medo é um sintoma central desses transtornos e sua aprendizagem é altamente dependente da atividade do fator neurotrófico derivado do cérebro (BDNF). Porém, será que a aprendizagem de medo mediada pelo BDNF deve ser considerada um alvo para o desenvolvimento de novos tratamentos para transtornos da ansiedade, TOC e transtornos relacionados? Revisamos as evidências que sugerem que a expressão de BDNF é necessária para a aquisição do medo condicionado, bem como para a evocação de sua extinção. Descrevemos os resultados relacionados a aprendizagem de medo, manipulação genética e epigenética da expressão de Bdnf em animais e variantes alélicas de BDNF em seres humanos. Posteriormente, discutimos como a manipulação dos níveis de BDNF representa um alvo em potencial para o tratamento, o que pode aumentar os benefícios das terapias que extinguem o medo previamente condicionado.