Familial misophonia or selective sound sensitivity syndrome: evidence for autosomal dominant inheritance? / Misofonia familiar ou síndrome da sensibilidade seletiva a sons: evidência de herança autossômica dominante?

Abstract Introduction: Misophonia is a recently described, poorly understood and neglected condition. It is characterized by strong negative reactions of hatred, anger or fear when subjects have to face some selective and low level repetitive sounds. The most common ones that trigger such aversive reactions are those elicited by the mouth (chewing gum or food, popping lips) or the nose (breathing, sniffing, and blowing) or by the fingers (typing, kneading paper, clicking pen, drumming on the table). Previous articles have cited that such individuals usually know at least one close relative with similar symptoms, suggesting a possible hereditary component. Objective: We found and described a family with 15 members having misophonia, detailing their common characteristics and the pattern of sounds that trigger such strong discomfort. Methods: All 15 members agreed to give us their epidemiological data, and 12 agreed to answer a specific questionnaire which investigated the symptoms, specific trigger sounds, main feelings evoked and attitudes adopted by each participant. Results: The 15 members belong to three generations of the family. Their age ranged from 9 to 73 years (mean 38.3 years; median 41 years) and 10 were females. Analysis of the 12 questionnaires showed that 10 subjects (83.3%) developed the first symptoms during childhood or adolescence. The mean annoyance score on the Visual Analog Scale from 0 to 10 was 7.3 (median 7.5). Individuals reported hatred/anger, irritability and anxiety in response to sounds, and faced the situation asking to stop the sound, leaving/avoiding the place and even fighting. The self-reported associated symptoms were anxiety (91.3%), tinnitus (50%), obsessive-compulsive disorder (41.6%), depression (33.3%), and hypersensitivity to sounds (25%). Conclusion: The high incidence of misophonia in this particular familial distribution suggests that it might be more common than expected and raises the possibility of having a hereditary etiology.

Resumo Introdução: A misofonia é uma condição recentemente descrita, mal compreendida e negligenciada. É caracterizada por fortes reações negativas de ódio, raiva ou medo quando os indivíduos precisam enfrentar alguns sons repetitivos seletivos e de baixa intensidade. Os mais comuns que desencadeiam tais reações aversivas são aqueles provocados pela boca (mascar goma ou mastigar comida, estalar os lábios) ou nariz (respirando, cheirando e soprando) ou pelos dedos (digitando, amassando papel, clicando a caneta, tamborilando na mesa). Artigos anteriores citam que esses indivíduos geralmente conhecem pelo menos um parente próximo com sintomas semelhantes, sugerindo um possível componente hereditário. Objetivo: Encontramos e descrevemos uma família com 15 membros com misofonia, detalhando suas características comuns e o padrão de sons que desencadeiam um desconforto tão forte. Método: Todos os 15 membros concordaram em nos fornecer seus dados epidemiológicos e 12 concordaram em responder a um questionário específico que investigou os sintomas, sons de gatilho específicos, principais sentimentos evocados e atitudes adotadas por cada participante. Resultados: Os 15 membros pertencem a três gerações da família. A idade variou de 9 a 73 anos (média de 38,3 anos, mediana de 41 anos) e 10 eram mulheres. A análise dos 12 questionários mostrou que 10 indivíduos (83,3%) desenvolveram os primeiros sintomas durante a infância ou a adolescência. A média do escore de irritação na Escala Visual Analógica de 0 a 10 foi de 7,3 (mediana 7,5). Os indivíduos relataram sentimentos de ódio/raiva, irritabilidade e ansiedade em resposta a sons, e enfrentaram a situação pedindo para interromper o som, deixando/evitando o lugar e até mesmo discutindo. Os sintomas associados auto-relatados foram ansiedade (91,3%), zumbido (50%), transtorno obsessivo-compulsivo (41,6%), depressão (33,3%) e hipersensibilidade aos sons (25%). Conclusão: A alta incidência de misofonia nessa distribuição familiar em particular sugere que possa ser mais comum do que o esperado e suscita a possibilidade de haver uma etiologia hereditária.

Neurochemical and behavioral characterization of neuronal glutamate transporter EAAT3 heterozygous mice

BACKGROUND: Obsessive-compulsive disorder (OCD) is a severe neuropsychiatric condition affecting 1-3% of the worldwide population. OCD has a strong genetic component, and the SLC1A1 gene that encodes neuronal glutamate transporter EAAT3 is a strong candidate for this disorder. To evaluate the impact of reduced EAAT3 expression in vivo, we studied male EAAT3 heterozygous and wild-type littermate mice using a battery of behavioral paradigms relevant to anxiety (open field test, elevated plus maze) and compulsivity (marble burying), as well as locomotor activity induced by amphetamine. Using high-performance liquid chromatography, we also determined tissue neurotransmitter levels in cortex, striatum and thalamus-brain areas that are relevant to OCD. RESULTS: Compared to wild-type littermates, EAAT3 heterozygous male mice have unaltered baseline anxiety-like, compulsive-like behavior and locomotor activity. Administration of acute amphetamine (5 mg/kg intraperitoneally) increased locomotion with no differences across genotypes. Tissue levels of glutamate, GABA, dopamine and serotonin did not vary between EAAT3 heterozygous and wild-type mice. CONCLUSIONS: Our results indicate that reduced EAAT3 expression does not impact neurotransmitter content in the corticostriatal circuit nor alter anxiety or compulsive-like behaviors.

Symmetry symptoms in obsessive-compulsive disorder: clinical and genetic correlates

Objective: In obsessive-compulsive disorder (OCD), symmetry-related symptoms may be important. Although clinical correlates of symmetry-related symptoms have been identified in OCD, few data exist on genetic associations. Animal studies indicate involvement of dopamine in symmetry-related behavior, suggesting this may be relevant to analogous symptoms in OCD. Alterations in dopamine may also reflect environmental influences. However, the association of symmetry-related symptomatology, early adversity, and polymorphisms in dopaminergic genes has not been investigated in OCD. Methods: Clinical information and polymorphisms in key dopaminergic genes were compared between OCD patients with primary symmetry symptoms and those without. Results: OCD patients with primary symmetry symptoms comprised 46.6% (n=210) of the sample (n=451), and were older (p < 0.01), had longer illness duration (p < 0.01), higher OCD severity scores (p = 0.01), and greater comorbidity (p < 0.01) than those without. In Caucasians (n=343), genotype frequency differed significantly between groups for ANKK1 rs1800497, with more OCD patients with symmetry symptoms being homozygous for the A2 (CC) genotype (χ2 = 7.296; p = 0.026). Conclusion: Symmetry symptoms have some distinct clinical features and may represent a marker of severity in OCD. However, clinical associations, in combination with the association found with the ANKK1 rs1800497 A2 variant, suggest that primary symmetry symptoms may represent a distinctive clinical and psychobiological profile.

Neuropsychological dysfunction in adults with early-onset obsessive-compulsive disorder: the search for a cognitive endophenotype

Objective: Evidence suggests that early-onset obsessive-compulsive disorder (OCD) is an etiologically distinct subtype of OCD. The objective of the present work was to search for neurocognitive endophenotypes of early-onset OCD based on assessments of attention, memory, and executive function in patients with the disorder and their unaffected siblings. Methods: We compared the performance of 40 adult patients with early-onset OCD, 40 of their unaffected siblings, and 40 unrelated healthy controls on a neuropsychological battery designed for this study. We searched for associations among test performance, demographic variables (age, sex and years of education) and clinical symptoms of early-onset OCD. Results: Patients performed significantly worse than healthy controls on the Tower of Hanoi, and the Stroop and Wisconsin tests, indicating impairments in planning, mental flexibility and inhibitory control. The performance of the unaffected first-degree siblings of patients with early-onset OCD on the Stroop and Wisconsin tests also differed from that of healthy controls. Symptom severity in early-onset OCD was strongly correlated with performance on the Tower of Hanoi. Conclusions: Our findings support the existence of specific executive function deficits in patients with early-onset OCD. Relatives presented an intermediate phenotype between patients and controls, suggesting that executive functions such as mental flexibility and response inhibition may be considered candidate endophenotypes of early-onset OCD. .

Association study between functional polymorphisms in the TNF-alpha gene and obsessive-compulsive disorder / Estudo de associação entre polimorfismos funcionais do gene do TNF-alfa e transtorno obsessivo-compulsivo

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 χ² 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.

O transtorno obsessivo-compulsivo (TOC) é um quadro psiquiátrico de prevalência considerável na população e de etiologia desconhecida. No entanto, há evidências de que o sistema imunológico pode desempenhar um papel importante em sua patogênese. No presente estudo, dois polimorfismos (rs1800795 e rs361525), localizados na região promotora do gene que codifica a citocina conhecida como fator de necrose tumoral alfa (TNFA), foram genotipados em 183 pacientes com TOC e 249 controles saudáveis. Os testes estatísticos foram realizados utilizando-se o software PLINK®. Assim, evidenciou-se que o alelo A do polimorfismo rs361525 apresentava associação estatisticamente significante com o TOC (p=0,007). A presença de marcadores genéticos, tais como genes que codificam citocinas inflamatórias, associados com TOC, confere suporte adicional ao papel do sistema imunológico na patogênese desse transtorno.

Endophenotypes and serotonergic polymorphisms associated with treatment response in obsessive-compulsive disorder

OBJECTIVES: Approximately 40-60% of obsessive-compulsive disorder patients are nonresponsive to serotonin reuptake inhibitors. Genetic markers associated with treatment response remain largely unknown. We aimed (1) to investigate a possible association of serotonergic polymorphisms in obsessive-compulsive disorder patients and therapeutic response to selective serotonin reuptake inhibitors and (2) to examine the relationship between these polymorphisms and endocrine response to intravenous citalopram challenge in responders and non-responders to serotonin reuptake inhibitors and in healthy volunteers. METHODS: Patients with obsessive-compulsive disorder were classified as either responders or non-responders after long-term treatment with serotonin reuptake inhibitors, and both groups were compared with a control group of healthy volunteers. The investigated genetic markers were the G861C polymorphism of the serotonin receptor 1Dβ gene and the T102C and C516T polymorphisms of the serotonin receptor subtype 2A gene. RESULTS: The T allele of the serotonin receptor subtype 2A T102C polymorphism was more frequent among obsessive-compulsive disorder patients (responders and non-responders) than in the controls (p<0.01). The CC genotype of the serotonin receptor subtype 2A C516T polymorphism was more frequent among the non-responders than in the responders (p<0.01). The CC genotype of the serotonin receptor subtype 1Dβ G681C polymorphism was associated with higher cortisol and prolactin responses to citalopram (p<0.01 and p<0.001, respectively) and with a higher platelet-rich plasma serotonin concentration among the controls (p<0.05). However, this pattern was not observed in the non-responders with the same CC genotype after chronic treatment with serotonin reuptake inhibitors. This CC homozygosity was not observed in the responders.

Gender differences in obsessive-compulsive disorder: a literature review / Diferenças de gênero no transtorno obsessivo-compulsivo: uma revisão da literatura

INTRODUCTION: Obsessive-compulsive disorder (OCD) is a heterogeneous condition, in which subtypes have been proposed. Previous studies suggested that gender plays a relevant role in OCD phenotypic expression. This study aimed to review the literature on gender differences in clinical, genetic or familial aspects of OCD. METHOD: A conventional review was conducted, including all papers that investigated demographic, clinical, and genetic aspects of OCD according to gender. The search was based on data available in Medline and PsycINFO databases in the last 20 years, using as keywords: obsessive-compulsive disorder; and: gender, sex, male, female, demographic characteristics, clinical features, clinical characteristics, genetic, genes, genetics gender OCD, genes OCD, genes OCD males, genes OCD females. RESULTS: Sixty three of 487 phenotypical and genetics studies were selected. Most studies indicate that male patients are more likely than females to be single, present early onset of symptoms and chronic course of the disorder, greater social impairment, more sexual-religious and aggressive symptoms, and greater comorbidity with tic and substance use disorders. Female patients present more contamination/cleaning symptoms and greater comorbidity with eating and impulse-control disorders. Genetic and family studies are inconclusive, but suggest that gender may play a role in the disease expression. CONCLUSIONS: Gender is a relevant factor that should be taken into account when evaluating OCD patients. More studies are necessary to determine whether in fact it defines a homogeneous and particular group in OCD.

INTRODUÇÃO: O transtorno obsessivo-compulsivo (TOC) é um quadro heterogêneo, no qual subtipos têm sido propostos. Estudos anteriores sugerem que gênero desempenha papel relevante na expressão fenotípica. O objetivo foi realizar uma revisão convencional da literatura sobre diferenças de gênero em relação a aspectos clínicos e genéticos ou familiares do TOC. MÉTODO: Realizou-se uma revisão convencional da literatura incluindo todos os artigos que investigaram aspectos sociodemográficos, clínicos e genéticos do TOC, de acordo com o gênero. A pesquisa foi baseada em publicações disponíveis nas bases de dados Medline e PsycInfo nos últimos 20 anos, usando como palavras-chave: obsessive-compulsive disorder (OCD), e: gender, sex, male, female, demographic characteristics, clinical features, clinical characteristics, genetic, genes, genetics gender OCD, genes OCD, genes OCD males, genes OCD females. RESULTADO: Sessenta e três artigos de fenótipo e genética foram selecionados. Na maioria dos estudos, o sexo masculino associou-se mais que o feminino com: ser solteiro, apresentar início mais precoce dos sintomas, maior prejuízo social, mais sintomas sexuais, religiosos e de agressão, e mais comorbidade com transtorno de tiques e abuso de substâncias. Pacientes do sexo feminino apresentam mais sintomas de contaminação/limpeza e mais comorbidade com transtornos alimentares e do controle de impulsos. Estudos genéticos e familiares são controversos, mas indicam que o gênero pode desempenhar um papel na expressão da doença. CONCLUSÃO: Gênero é um fator relevante a ser considerado na avaliação de pacientes com TOC. São necessários mais estudos para determinar se este fator define de fato um grupo homogêneo e particular de TOC.

Associations between polymorphic variants of the tryptophan hydroxylase 2 gene and obsessive-compulsive disorder / Associação entre polimorfismos do gene da triptofano hidroxilase 2 e o transtorno obsessivo-compulsivo

OBJECTIVE: A substantial body of evidence suggests that obsessive-compulsive disorder has a genetic component, and substantial candidate genes for the disorder have been investigated through association analyses. A particular emphasis has been placed on genes related to the serotonergic system, which is likely to play an important role in the pathogenesis of obsessive-compulsive disorder. The gene for tryptophan hydroxylase 2, which is a rate limiting enzyme in serotonin synthesis, is considered an important candidate gene associated with psychiatric disorders. METHOD: Our sample consisted of 321 subjects (107 diagnosed with obsessive-compulsive disorder and 214 healthy controls), which were genotyped for eight tagSNPs (rs4448731, rs4565946, rs11179000, rs7955501, rs10506645, rs4760820, rs1487275 and rs10879357) covering the entire human tryptophan hydroxylase 2 gene. Statistical analyses were performed using UNPHASED, version 3.0.12, and Haploview®. RESULTS: Single markers, genotype analysis did not show a significant genetic association with obsessive-compulsive disorder. A significant association between the T-C-T (rs4448731, rs4565946, rs10506645) and C-A-T (rs4565946, rs7955501, rs10506645) haplotypes and obsessive-compulsive disorder was observed, as well as a strong linkage disequilibrium between SNPs rs4448731 and rs4565946, and SNPs rs10506645 and 4760820. DISCUSSION: Our research has not demonstrated the existence of associations between the eight SNPs of TPH2 and obsessive-compulsive disorder. However, two LD and two haplotypes areas were demonstrated, thus suggesting that more studies in TPH2 are needed to investigate the role of tryptophan hydroxylase 2 variants in obsessive-compulsive disorder.

OBJETIVO: Diversos estudos demonstram que o transtorno obsessivo-compulsivo apresenta considerável contribuição genética, com diversos genes candidatos tendo sido estudados por meio de estudos de associação. Como alterações do sistema serotonérgico estão associadas ao transtorno obsessivo-compulsivo, o gene da triptofano hidroxilase 2, enzima limitante da síntese da serotonina, é plausível candidato para estudos. MÉTODO: Nossa amostra é composta de 321 sujeitos (107 pacientes com transtorno obsessivo-compulsivo e 214 controles) e investigamos oito tagSNPs (rs4448731, rs4565946, rs11179000, rs7955501, rs10506645, rs4760820, rs1487275 e rs10879357) do gene da triptofano hidroxilase 2. Análise estatística foi realizada com os programas UNPHASED e Haploview. RESULTADOS: Análise de frequência alélica e genotípica entre casos e controles não evidenciaram diferenças estatisticamente significativas. No entanto, observamos maior prevalência dos haplótipos T-C-T (rs4448731, rs4565946, rs10506645) e C-A-T (rs4565946, rs7955501, rs10506645) entre os pacientes, assim como duas regiões com importantes desequilíbrios de ligação (SNPs rs4448731 e rs4565946; SNPs rs10506645 e 4760820). DISCUSSÃO: Nossos achados não demonstraram uma associação entre os SNPs do gene da TPH2 e o transtorno obsessivo-compulsivo, porém mais estudos são necessários, já que fortes desequilíbrios de ligação foram demonstrados, assim como dois haplótipos.

Association study between genetic monoaminergic polymorphisms and OCD response to clomipramine treatment / Estudo de associação entre polimorfismos genéticos monoaminérgicos e resposta à clomipramina no tratamento do TOC

In the present paper, we investigated the 5HTTLPR and STin2 polymorphisms in the promoter region of the serotonin transporter gene (SLC6A4), the G861C polymorphism (rs6296) of the serotonin receptor 1D beta (HTR1B), the T102C (rs6113) and C516T (rs6305) polymorphisms of the serotonin receptor gene subtype 2A (HTR2A), the DAT UTR, DAT intron 8 and DAT intron 14 of the dopamine transporter gene (SLC6A3), the Val-158-Met (rs4680) polymorphism of the COMT and the silent mutation G1287A (rs5569) in the norepinephrine transporter gene (SLC6A2). We genotyped 41 obsessive-compulsive disorder (OCD) outpatients, classified as good-responders (n=27) and poor-responders (n=14) to treatment with clomipramine according to the Yale Brown Obsessive-Compulsive Scale (YBOCS). Patients who achieved a reduction in symptoms of 40 percent or more in YBOCS after 14 weeks of treatment were considered good-responders. Genotypes and alleles distribution of the investigated polymorphisms were compared between both groups. We did not find association between the studied polymorphisms and clomipramine response in our sample.

No presente estudo, investigaram-se os polimorfismos 5HTTLPR e STin2 da região promotora do gene transportador de serotonina (SLC6A4), o G861C (rs6296) do receptor de serotonina 1D beta (HTR1B), os polimorfismos T102C (rs6113) e C516T (rs6305) do gene do receptor da serotonina subtipo 2A (HTR2A), os polimorfismos UTR, intron 8 e intron 14 do gene transportador de dopamina (SLC6A3), o Val-158-Met (rs4680) da COMT e a mutação G1287A (rs5569) do gene do transportador de norepinefrina (SLC6A2). Foram genotipados 41 pacientes com transtorno obsessivo-compulsivo (TOC), classificados como bons-respondedores (n=27) e maus-respondedores (n=14) ao tratamento com clomipramina, por meio do uso da Escala de Sintomas Obsessivos-Compulsivos Yale Brown (YBOCS). Foram considerados bons-respondedores os pacientes que tiveram redução nos sintomas em 40 por cento ou mais na YBOCS, após 14 semanas de tratamento. A distribuição dos genótipos e alelos estudados foi comparada entre os dois grupos. Não foi encontrada associação entre estes polimorfismos investigados e a resposta à clomipramina na amostra estudada.

Association of serotonin transporter gene polymorphisms with obsessive-compulsive disorder (OCD) in a south Indian population.

Background and Objectives: Serotonin transporter polymorphisms, 5-HTTVNTR and 5-HTTLPR, have been found to be associated with obsessive-compulsive disorder (OCD) and particularly with neurotic characteristics. In the present study we looked for an association between OCD and these polymorphisms in OCD patients and controls of south Indian origin. Methods: 5-HTTVNTR and 5-HTTLPR/rs25531 were genotyped in 93 OCD patients and 92 healthy controls. The allelic distribution and genotype frequency in cases and controls were compared using chi square test. In order to test for the effects of genotype on heterogeneity of the illness, linear regression analysis was undertaken for co-morbid depression status and YBOCS score (severity index). Results: There was no significant association with the 5-HTTVNTR or the 5-HTTLPR polymorphism. No significant association of OCD with the 5-HTTLPR genotype was found even on inclusion of the rs25531 locus, which is part of the transcription factor binding site as reported in earlier studies. However, severity of the illness showed a modest association with the dominant model. Interpretation & conclusions: Our data show that genetic variation in the SLC6A4 gene regulatory region may not have a significant effect on OCD in the present population. Further replication in a large and independent cohort with an equal number of female subjects would help to ascertain if the absence of association in this cohort is due to the nullifying effect of the larger proportion of male subjects in our sample population. The marginal effect of the 5-HTTLPR (A/G) genotype obtained on linear regression with disease severity is suggestive of a potential role for this locus in the disease process.

O conceito do insight em pacientes com transtorno obsessivo-compulsivo / The concept of insight in patients with obsessive-compulsive disorder

OBJETIVO: Atualizar os clínicos sobre a existência de um possível subtipo do transtorno obsessivo-compulsivo caracterizado por pouco insight. MÉTODO: Revisão opinativa baseada em estudos indexados na base de dados PubMed e PsychINFO, identificados por meio dos unitermos "obsessive-compulsive disorder" e "insight" ou "ego-dystonic" e publicados entre 1966 e outubro de 2009. Os resultados foram examinados de acordo com a estratégia utilizada para abordar o insight, i.e. categórica vs. dimensional. RESULTADOS: Análise dos estudos nos permitiu identificar pontos que colocam em dúvida a existência de um subtipo do transtorno obsessivo-compulsivo bem delimitado caracterizado por pouco insight. Estes pontos incluem 1) prevalência extremamente variável do transtorno obsessivo-compulsivo com insight reduzido encontrada em estudos categóricos, 2) homogeneidade dos achados fenotípicos (i.e. maior gravidade) associados a baixo insight em estudos categóricos e dimensionais e 3) ausência de estudos que investigam "zonas de raridade" entre as formas de transtorno obsessivo-compulsivo com pouco e bom insight. CONCLUSÃO: Embora uma abordagem categórica do insight no transtorno obsessivo-compulsivo seja importante em ambientes clínicos, uma vez que neles existem demandas prementes para tomada de decisões, a abordagem dimensional do insight parece refletir de forma mais fidedigna o fenômeno apresentado pelos pacientes em tela.

OBJECTIVE: To update clinicians regarding the existence of a putative subtype of obsessive-compulsive disorder based on poor insight. METHOD: Opinionative review based on studies indexed in the PubMed and PsychINFO databases, identified by means of the keywords "obsessive-compulsive disorder" AND "insight" OR "ego-syntonic", and published between 1966 and October 2009. The results were analyzed according to the approach adopted, i.e. a categorical or dimensional view of insight in obsessive-compulsive disorder. RESULTS: The review of recent studies led us to identify some issues that cast doubts over the existence of a clear-cut poor insight subtype of obsessive-compulsive disorder. These issues include 1) an extremely variable prevalence of poor insight obsessive-compulsive disorder in categorical studies, 2) a significant degree of homogeneity in the phenotypical findings (i.e. greater severity) associated with lower levels of insight in obsessive-compulsive disorder in both categorical and dimensional studies and, 3) a lack of studies investigating zones of rarity between poor and good insight obsessive-compulsive disorder. CONCLUSION: Although a categorical approach to the insight issue in obsessive-compulsive disorder is still important in clinical settings, where decision-making is often a critical issue, a dimensional approach seems to reflect levels of impairment in these patients more reliably.

The GABA A-Receptor 2 (GABRG2) Gene in obsessive-compulsive disorder / O gene do receptor GABA A-2 (GABRG2) no transtorno obsessivo-compulsivo

OBJECTIVE: The γ-aminobutyric acid type A (GABA A) system may be implicated in obsessive-compulsive disorder, based on its major role in modulation of anxiety and its function as the principal inhibitory neurotransmitter system in the cortex. In addition, glutamatergic/GABAergic mechanisms appear to play a role in the pathophysiology of obsessive-compulsive disorder, making the GABA A receptor-γ2 (GABργ2) gene a good candidate for susceptibility in this disorder. METHOD: 118 probands meeting DSM-IV criteria for primary obsessive-compulsive disorder and their available parents were recruited for participation in this study and informed consent was obtained. An NciI restriction site polymorphism in the second intron was genotyped and data was analyzed using the Transmission Disequilibrium Test. RESULTS: In total, 61 of the participating families were informative (i.e., with at least one heterozygous parent). No biases were observed in the transmission of either of the two alleles (χ2 = 0.016, 1 d.f., p = 0.898) to the affected probands in the total sample. CONCLUSION/DISCUSSION: While these results do not provide support for a major role for the GABA A receptor-γ2 in obsessive-compulsive disorder, further investigations of this gene in larger samples are warranted.

OBJETIVO: O sistema gabaérgico tipo A (GABA A) pode estar implicado no transtorno obsessivo-compulsivo devido ao seu grande papel na modulação da ansiedade e da sua função como o principal neurotransmissor inibidor no córtex. Além disso, mecanismos glutamatérgicos/gabaérgicos parecem desempenhar um papel na fisiopatologia do transtorno obsessivo-compulsivo, tornando o gene do receptor GABA A-γ2 (GABRG2) um bom gene candidato para a suscetibilidade genética a este transtorno. MÉTODO: 118 probandos que preencheram os critérios do DSM-IV para transtorno obsessivo-compulsivo primário e seus pais (quando disponíveis) foram recrutados para a participação neste estudo; consentimento informado foi obtido. Um polimorfismo no sítio de restrição da enzima NciI, localizado no íntron 2, foi genotipado e os dados foram analisados utilizando-se o Teste de Desequilíbrio de Transmissão. RESULTADOS: No total, 61 das famílias participantes foram informativas (ou seja, com pelo menos um progenitor heterozigoto). Não foi observado desequilíbrio de transmissão de qualquer um dos dois alelos (χ2 = 0,016, 1 g.l., p = 0,898) aos probandos afetados. CONCLUSÃO/DISCUSSÃO: Apesar de estes resultados não fornecerem suporte para um papel importante para o gene GABA A-γ2 no transtorno obsessivo-compulsivo, novas investigações desse gene em amostras maiores são justificadas.

Association study between the -62A/T NFKBIL1 polymorphism and obsessive-compulsive disorder / Estudo de associação entre o polimorfismo -62A/T NFKBIL1 e o transtorno obsessivo-compulsivo

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 (χ2 = 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.

OBJETIVO: Evidências advindas de estudos de família e de genética molecular têm dado suporte à hipótese do envolvimento de mecanismos imunológicos na fisiopatologia do transtorno obsessivo-compulsivo. Tem sido sugerido que o potencializador do fator nuclear do polipeptídeo kappa light em células-B inibidoras-like 1 (NFKBIL1) é um modulador do sistema imunológico. Dada a importância do NFKBIL1 na resposta imunológica, o presente estudo investigou o polimorfismo -62A/T (rs2071592), localizado na região promotora de seu gene, como fator de risco genético para o desenvolvimento do transtorno obsessivo-compulsivo. MÉTODO: O polimorfismo -62A/T do gene do NFKBIL1 foi investigado em uma amostra de 111 pacientes com o diagnóstico de transtorno obsessivo-compulsivo, de acordo com os critérios do DSM-IV, e 272 controles saudáveis emparelhados por idade e gênero. RESULTADOS: Não houve diferenças na distribuição genotípica entre pacientes e controles (χ2 = 0,98; 2 d.f.; p = 0,61). DISCUSSÃO: Apesar dos resultados negativos, estudos compreendendo mais polimorfismos no gene do NFKBIL, em amostras maiores, são necessários. Populações com diferentes origens étnicas também precisam ser avaliadas. CONCLUSÃO: Os resultados da presente investigação não evidenciam associação entre o polimorfismo -62A/T do gene do NFKBIL1 e o transtorno obsessivo-compulsivo nesta amostra brasileira.

Association analysis between a VNTR intron 8 polymorphism of the dopamine transporter gene (SLC6A3) and obsessive- compulsive disorder in a Brazilian sample

Family, twin and segregation analysis have provided evidences that genetic factors are implicated in the susceptibility for obsessive-compulsive disorder (OCD). Several lines of research suggest that the dopaminergic system may be involved in the pathophysiology of OCD. Thus, the aim of the present study was to investigate a possible association between a polymorphism located in intron 8 of the dopamine transporter gene (SLC6A3) and OCD in a Brazilian sample composed by 208 patients and 865 healthy controls. No statistically differences were observed in allelic and genotype distributions between cases and controls. No association was also observed when the sample was divided according to specific phenotypic features such as gender, presence of tic disorders co-morbidity and age at onset of obsessive-compulsive symptoms (OCS). Our results suggest that the intron 8 VNTR of the SLC6A3 investigated in this study is not related to the susceptibility for OCD in our Brazilian sample.

Estudos de família, gêmeos e de segregação têm demonstrado que fatores genéticos estão envolvidos na susceptibilidade para o desenvolvimento do transtorno obsessivo-compulsivo (TOC). Várias linhas de pesquisa sugerem que o sistema dopaminérgico possa estar envolvido na fisiopatologia do TOC. Assim, o objetivo do presente estudo foi investigar uma possível associação entre o polimorfismo localizado no intron 8 do gene do transportador da dopamina (SLC6A3) e o TOC em uma amostra brasileira composta por 208 pacientes e 865 controles sadios. Nenhuma diferença estatisticamente significante foi observada nas distribuições alélicas e genotípicas entre os grupos de pacientes e controles. Nenhuma associação também foi observada quando as amostras foram divididas de acordo com características fenotípicas específicas, tais como gênero, presença de co-morbidade com tiques e idade de início dos sintomas obsessivo-compulsivo (SOC). Nossos resultados sugerem que o VNTR do intron 8 investigado neste estudo não está relacionado com o TOC na nossa amostra brasileira.

Estudos de associação entre transtorno obsessivo-compulsivo e genes candidatos: uma revisão / Studies of association between the obsessive-compulsive disorder and candidate genes: a review

OBJETIVO: Nos últimos anos, o papel dos genes dos sistemas serotoninérgicos e dopaminérgicos tem sido sistematicamente investigado em pacientes com transtorno obsessivo-compulsivo (TOC), uma vez que esses neurotransmissores apresentam uma provável implicação na fisiopatologia do TOC. Este artigo objetiva revisar os principais resultados de estudos de associação entre genes candidatos e TOC. MÉTODOS: Revisão da literatura na base de dados Medline até agosto de 2006, utilizando as palavras-chave obsessive-compulsive disorder (OCD) e/ou gene(s), polymorphism(s), genetics. RESULTADOS: Inúmeros estudos têm apresentado resultados negativos ao compararem pacientes com TOC e controles, entretanto resultados positivos têm sido observados em pacientes com TOC com características clínicas particulares (sexo, idade de início, dimensão ou gravidade dos sintomas obsessivos ou compulsivos e presença de tiques). CONCLUSÃO: Para garantir a continuidade do avanço de estudos genéticos, é necessária a identificação de subgrupos homogêneos de pacientes com TOC. Diante desses grupos, será possível delinear endofenótipos confiáveis que permitam explorar de forma mais específica a contribuição dos diferentes genes na patogênese da doença.

OBJECTIVE: The obsessive compulsive-disorder (OCD) is a psychiatric disorder characterized by the presence of obsessions and compulsions. Its prevalence is of approximately 2 percent-3 percent in the general population. In the last years, genes of the serotoninergic and dopaminergic systems have been investigated as these neurotransmitters are probably involved in the pathophysiology of the OCD. This article aims at revising the results of studies of association between candidate genes and OCD. METHODS: Review of the literature in the Medline database until August of 2006, using the key words: obsessive-compulsive disorder, OCD and/or gene(s), polymorphism(s), genetics. RESULTS: A series of studies presented negative results when comparing OCD patients and controls. Nevertheless, positive results have been observed, when studying among OCD patients, distinct clinical features (gender, age of beginning, dimension and/or severity of the obsessive and/or compulsive symptoms, presence of tics). CONCLUSION: For the advance of genetic studies in OCD, it would be necessary to identify homogeneous subgroups of OCD patients. Based on these subgroups, it may be possible to define reliable endophenotypes that could lead to a more rational search for genes possibly involved in OCD pathogenesis.