Abstract Runs of homozygosity (ROH) in the human genome may be clinically relevant. The aim of this study was to report the frequency of increased ROH of the autosomal genome in individuals with neurodevelopmental delay/intellectual disability and/or multiple congenital anomalies, and to compare these data with a control group. Data consisted of calls of homozygosity from 265 patients and 289 controls. In total, 7.2% (19/265) of the patients showed multiple ROH exceeding 1% of autosomal genome, compared to 1.4% (4/289) in the control group (p=0.0006). Homozygosity ranged from 1.38% to 22.12% among patients, and from 1.53 to 2.40% in the control group. In turn, 1.9% (5/265) of patients presented ROH ≥10Mb in a single chromosome, compared to 0.3% (1/289) of individuals from the control group (p=0.0801). By excluding cases with reported consanguineous parents (15/24), the frequency of increased ROH was 3.4% (9/250) among patients and 1.7% (5/289) in the control group, considering multiple ROH exceeding 1% of the autosome genome and ROH ≥10Mb in a single chromosome together, although not statistically significant (p=0.1873). These results reinforce the importance of investigating ROH, which with complementary diagnostic tests can improve the diagnostic yield for patients with such conditions.

Abstract The aim of this study was to investigate the segregation patterns of molar incisor hypomineralization (MIH) in families, given the evidence that its etiology is influenced by genetics. Clinically, MIH may be detected in parents and/or siblings of MIH-affected children. Our study included children with at least one first permanent molar affected by MIH (proband) and their first-degree relatives (parents and siblings). The participants were examined clinically to detect MIH, according to the European Academy of Paediatric Dentistry criteria (2003). A total of 101 nuclear families (391 individuals) were studied. Proband diagnosis was followed by MIH classification of the subject, his parents and siblings, as affected, unaffected, or unknown. Segregation analysis was performed using the multivariate logistic regression model of the Statistical Analysis for Genetic Epidemiology package, and segregation models (general transmission, environmental, major gene, dominant, codominant and recessive models). The Akaike information criterion (AIC) was used to evaluate the most parsimonious model. In all, 130 affected individuals, 165 unaffected individuals, and 96 unknown individuals were studied. Severe MIH was found in 50.7% of the cases. A segregation analysis performed for MIH revealed the following different models: environmental and dominance (p = 0.05), major gene (p = 0.04), codominant (p = 0.15) and recessive models (p = 0.03). According to the AIC values, the codominant model was the most parsimonious (AIC = 308.36). Our results suggest that the codominant model could be the most likely for inheriting MIH. This result strengthens the evidence that genetic factors, such as multifactorial complex defect, influence MIH.

RESUMO Objetivo Identificar potenciais preditores clínicos e epidemiológicos de resposta terapêutica ao uso prolongado de lítio. Métodos Um total de 40 pacientes adultos em tratamento ambulatorial em um hospital universitário, com diagnóstico confirmado de transtorno afetivo bipolar e história de pelo menos seis meses de uso de lítio, teve sua resposta a essa medicação avaliada com a utilização de um instrumento padronizado. A escala ALDA leva em consideração informações clínicas obtidas de forma retrospectiva, em nosso estudo, por meio de minuciosa revisão dos prontuários médicos, para julgar a melhora clínica obtida com o tratamento (Critério A), corrigida pela identificação de possíveis fatores confundidores, tais como duração do tratamento, adesão e uso concomitante de outras drogas (Critério B), de forma a estimar a resposta que pode ser atribuída especificamente ao uso do lítio. Resultados Nosso estudo encontrou uma relação inversa entre o número de episódios de humor com a presença de sintomas psicóticos e o desfecho no tratamento com lítio. Conclusão Esses resultados reforçam a hipótese de que o lítio parece ser menos eficaz em pacientes com transtorno afetivo bipolar que manifestam sintomas psicóticos.

ABSTRACT Objetive To identify potential clinical and epidemiological predictors of long-term response to lithium treatment. Methods A total of 40 adult outpatients followed in an university hospital, with confirmed diagnosis of bipolar disorder and with history of lithium use for at least a six months period, had their response to this medication assessed through the use of a standardized instrument. The ALDA scale is based on retrospective clinical data, in our study assessed through a thoroughly reviewed of the medical charts, and is used to evaluate the clinical improvement with the treatment (Criterion A), corrected by the acknowledgement of possible confounding factors, such as duration of the treatment, compliance and concomitant use of additional medications (Criterion B), in order to estimate the response that can be specifically attributable to lithium. Results Our study found an inverse relation between the number of mood episodes with psychotic symptoms and lithium treatment outcome. Conclusion The results reinforce the hypothesis that lithium seems to be less efficacious in patients with bipolar disorder who present psychotic symptoms.

Fundamentos:Evidências sugerem que a paroxonase 1 (PON1) confere importantes propriedades antioxidantes e antiinflamatórias quando associada à lipoproteína de alta densidade (HDL).Objetivo:Investigar as relações entre o SNP p.Q192R da PON1, parâmetros bioquímicos e aterosclerose carotídea em uma amostra populacional brasileira assintomática e normolipidêmica.Métodos:Foram estudados 584 voluntários (mulheres, n = 326; homens, n = 258; idade entre 19-75 anos). Foi extraído DNA genômico total e o SNP foi detectado na plataforma de genotipagem TaqMan® SNP OpenArray®(Applied Biosystems, Foster City, CA). Foram dosadas lipoproteínas e apolipoproteínas plasmáticas, e a atividade da PON1 foi medida utilizando-se paraoxon como substrato. Foi utilizada ultrassonografia bidimensional de alta resolução para determinar a espessura íntimo‑medial das artérias carótidas (EIMc) e a presença de placas ateroscleróticas carotídeas em um subgrupo de indivíduos (n = 317).Resultados:A presença de p.192Q esteve associada a um aumento significativo da atividade da PON1 (RR = 12,30 (11,38); RQ = 46,96 (22,35); QQ = 85,35 (24.83) μmol/min; p < 0,0001), HDL-C (RR = 45 (37); RQ = 62 (39); QQ= 69 (29) mg/dL; p < 0,001) e apo A-1 (RR = 140,76 ± 36,39; RQ = 147,62 ± 36,92; QQ = 147,49 ± 36,65 mg/dL; p = 0,019). A análise de regressãostepwise mostrou que heterozigotos e portadores de p.192Q influenciaram 58% da atividade da PON1 em relação ao paraoxon. A análise de regressão linear univariada demonstrou que não houve associação entre o SNP p.Q192R e a EIMc média; como resultado, na análise de regressão múltipla nenhuma variável foi selecionada com 5% de significância. Os parâmetros estudados não se associaram à presença de placas carotídeas na análise de regressão logística.Conclusão:Em indivíduos de baixo risco, a presença da variante p.192Q daPON1 mostrou-se associada a um perfil lipídico plasmático benéfico e à ausência de aterosclerose de carótida.

Background:Evidences suggest that paraoxonase 1 (PON1) confers important antioxidant and anti-inflammatory properties when associated with high-density lipoprotein (HDL).Objective:To investigate the relationships between p.Q192R SNP ofPON1, biochemical parameters and carotid atherosclerosis in an asymptomatic, normolipidemic Brazilian population sample.Methods:We studied 584 volunteers (females n = 326, males n = 258; 19-75 years of age). Total genomic DNA was extracted and SNP was detected in the TaqMan® SNP OpenArray® genotyping platform (Applied Biosystems, Foster City, CA). Plasma lipoproteins and apolipoproteins were determined and PON1 activity was measured using paraoxon as a substrate. High-resolution β-mode ultrasonography was used to measure cIMT and the presence of carotid atherosclerotic plaques in a subgroup of individuals (n = 317).Results:The presence of p.192Q was associated with a significant increase in PON1 activity (RR = 12.30 (11.38); RQ = 46.96 (22.35); QQ = 85.35 (24.83) μmol/min; p < 0.0001), HDL-C (RR= 45 (37); RQ = 62 (39); QQ = 69 (29) mg/dL; p < 0.001) and apo A-I (RR = 140.76 ± 36.39; RQ = 147.62 ± 36.92; QQ = 147.49 ± 36.65 mg/dL; p = 0.019). Stepwise regression analysis revealed that heterozygous and p.192Q carriers influenced by 58% PON1 activity towards paraoxon. The univariate linear regression analysis demonstrated that p.Q192R SNP was not associated with mean cIMT; as a result, in the multiple regression analysis, no variables were selected with 5% significance. In logistic regression analysis, the studied parameters were not associated with the presence of carotid plaques.Conclusion:In low-risk individuals, the presence of the p.192Q variant ofPON1 is associated with a beneficial plasma lipid profile but not with carotid atherosclerosis.

Epilepsia mioclônica juvenil (EMJ) representa 26% das síndromes epilépticas idiopáticas generalizadas. Níveis elevados de atividade da trombina estão intimamente envolvidos no desenvolvimento de distúrbios neurológicos, incluindo epilepsia. A variante c.20210G>A (rs1799963) do gene de protrombina, que altera a estabilidade do RNAm, está associada com altos níveis de protrombina no plasma. Objetivo: Investigar se o SNP rs1799963 é um fator de risco para EMJ em uma amostra da população do nordeste brasileiro. Resultados : O polimorfismo foi genotipado em 123 pacientes e 207 controles usando a reação de polimerase em cadeia com restrição de polimorfismo. Não observamos diferença significativa nas frequências alélicas e genotípicas deste polimorfismo, entre as populações de pacientes e controle. Conclusão : Estes resultados não demonstram evidências para uma associação do polimorfismo rs1799963 com EMJ. Estudos posteriores, incluindo outros tipos de epilepsia, são necessários para investigar o envolvimento do gene protrombina na susceptibilidade genética a crises crônicas.

Juvenile myoclonic epilepsy (JME) accounts for 26% of generalized idiopathic epileptic syndromes. The highest levels of thrombin activity are closely involved in the development of neurological diseases, including epilepsy. The prothrombin c.20210G>A (rs1799963) variation, which alters prothrombin mRNA stability, is associated with high plasma prothrombin levels. Objective : The present study was designed to investigate whether the SNP rs1799963 is a risk factor for JME in the northeastern Brazilian population. Results : The polymorphism was genotyped in 207 controls and 123 patients using polymerase chain reaction-restriction fragment length polymorphism method. No significant differences were observed in the genotype and allele frequencies of this polymorphism between cases and controls. Conclusion : These results present no evidence for an association of rs1799963 with JME. Further studies including other types of epilepsy are required to investigate the involvement of prothrombin gene in the genetic susceptibility to chronic seizure.

RNA interference (RNAi) is a natural endogenous process by which double-stranded RNA molecules trigger potent and specific gene silencing in eukaryotic cells and is characterized by target RNA cleavage. In mammals, small interfering RNAs (siRNAs) are the trigger molecules of choice and constitute a new class of RNA-based antiviral agents. In an efficient RNAi response, the antisense strand of siRNAs must enter the RNA-induced silencing complex (RISC) in a process mediated by thermodynamic features. In this report, we hypothesize that silent mutations capable of inverting thermodynamic properties can promote resistance to siRNAs. Extensive computational analyses were used to assess whether continuous selective pressure that promotes such mutations could lead to the emergence of viral strains completely resistant to RNAi (i.e., prone to transfer only the sense strands to RISC). Based on our findings, we propose that, although synonymous mutations may produce functional resistance, this strategy cannot be systematically adopted by viruses since the longest RNAi-refractory sequence is only 10 nt long. This finding also suggests that all mRNAs display fluctuating thermodynamic landscapes and that, in terms of thermodynamic features, RNAi is a very efficient antiviral system since there will always be sites susceptible to siRNAs.

INTRODUÇÃO: MicroRNAs (miRNAs) são pequenas moléculas de RNA (21-24 nt) que regulam negativamente a expressão gênica, seja pela repressão da tradução ou pela degradação do RNA mensageiro. Essas moléculas estão envolvidas em muitos processos importantes incluindo diferenciação celular, neurogênese, formação do sistema nervoso entre outras. A epilepsia de lobo temporal mesial e as epilepsias causadas por disgenesias corticias estão entre as principais causas de refratariedade ao tratamento medicamentos nas epilepsias. OBJETIVOS: Os objetivos desse trabalho foram elucidar o perfil de expressão dos miRNAs e investigar a regulação dos mesmos na epilepsia de lobo temporal mesial (ELTM) e nas displasias corticais focais (DCFs). MÉTODOS: RNA total foi extraído de tecidos de hipocampo e de neocórtex, tanto congelados fresco como em parafina, de pacientes que se submeteram a cirurgia para controle das crises. Para comparação utilizamos tecidos equivalentes provindos de autópsia. Para a análise da expressão dos miRNAs, o RNA extraído foi utilizado em reações de PCR em tempo real (157 miRNAs analisados) ou em chips de microarranjos (847 miRNAs analisados). RESULTADOS: Análises de bioinformática identificaram três miRNAs com expressão significantemente alterada em pacientes com ELTM: let-7d, miR-29b e miR-30d; enquanto nos pacientes com DCFs foram encontrados 23 microRNAs diferencialmente expressos, sendo que o padrão de expressão foi diferente em diferentes formas histopatológicas de DCFs. CONCLUSÕES: Os possíveis genes regulados pelos miRNAs com expressão alterada nos tecidos com esclerose mesial temporal (EMT) estão relacionados principalmente com neurogênese e apoptose. Enquanto que nas DCFs estes estão predominantemente relacionados à proliferação e migração celular. Nossos resultados demonstram a relevância da regulação por miRNAs nos processos moleculares que culminam com a formação das lesões presentes na EMT e nas DCFs. A complexidade dessa regulação começa agora a ser desvendada e pode resultar não só na elucidação dos processos biológicos envolvidos, como também na identificação de biomarcadores de potencial uso clínico nas epilepsias.

BACKGROUND: MicroRNAs (miRNAs) are small RNA molecules (21-24 nt) that negatively regulate gene expression, either by repression of translation or by degradation of messenger RNA. These molecules are involved in many important processes including cell differentiation, neurogenesis, formation of nervous system and others. Mesial temporal lobe epilepsy and epilepsy caused by cortical dysgenesis are among the leading causes of drug resistant epilepsy. OBJECTIVES: The objectives of this study were to characterize the expression profile of miRNAs and to investigate their regulation in mesial temporal lobe epilepsy (MTL) and in focal cortical dysplasias (FCDs). METHODS: Total RNA was extracted from hippocampal and neocortical tissue, maintained in paraffin or fresh-frozen, from patients who underwent surgery for seizure control. For comparison we used tissue obtained from autopsy. RNA was extracted and used in real time PCR reactions (157 miRNAs analyzed) or microarray chips (847 miRNAs analyzed). RESULTS: Bioinformatics analyzes identified three miRNAs with expression significantly different in patients with MTLE: let-7d, miR-29b and miR-30d; while in patients with FCDs we found 23 microRNAs differentially expressed. In addition, we found that different pathological forms of had different molecular signatures. CONCLUSIONS: The possible genes regulated by miRNAs with differential expression in tissue with mesial temporal sclerosis (MTS) are mainly related to neurogenesis and apoptosis. While in DCFs they were predominantly related to cell proliferation and migration. Our results demonstrate the importance of miRNA regulation the in molecular processes that lead to the lesions present in the MTS and the FCDs.

Several studies have shown that mutations and polymorphisms in clock genes are associated with abnormal circadian parameters in humans and also with more subtle non-pathological phenotypes like chronotypes. However, there have been conflicting results, and none of these studies analyzed the combined effects of more than one clock gene. Up to date, association studies in humans have focused on the analysis of only one clock gene per study. Since these genes encode proteins that physically interact with each other, combinations of polymorphisms in different clock genes could have a synergistic or an inhibitory effect upon circadian phenotypes. In the present study, we analyzed the combined effects of four polymorphisms in four clock genes (Per2, Per3, Clock and Bmal1) in people with extreme diurnal preferences (morning or evening). We found that a specific combination of polymorphisms in these genes is more frequent in people who have a morning preference for activity and there is a different combination in individuals with an evening preference for activity. Taken together, these results show that it is possible to detect clock gene interactions associated with human circadian phenotypes and bring an innovative idea of building a clock gene variation map that may be applied to human circadian biology.

OBJETIVOS: As malformações do córtex cerebral (MCC) são uma causa importante de epilepsia. Nossas metas foram: triagem de mutações em genes associados às MCC (FLN1, LIS1, DCX e EMX2), investigar funcionalmente as mutações e mapear o locus para polimicrogiria perisylviana familiar. MÉTODOS: A triagem de mutações foi realizada por PCR, DHPLC e sequênciamento. Estudo funcional foi realizado por RT-PCR, PCR em tempo real e HUMARA. O estudo de ligação foi realizado por PCR e análise com programas Fragment Profiler® e MLINK®. RESULTADOS: Mutações deletérias foram identificadas em 3/108 pacientes. Uma mutação de splicing (G987C) em FLN1 foi identificada em duas pacientes aparentadas com heterotopia nodular periventricular. Mudança no padrão de inativação do cromossomo X é responsável pelas diferenças clínicas entre as pacientes. Uma substituição A1385C (H277P) foi identificada em LIS1 em um indivíduo com lissencefalia. Alterações neutras foram identificadas em DCX e EMX2. A análise de ligação identificou um locus em Xq27.2-Xq27.3 para polimicrogiria familiar. CONCLUSÃO: Mosaicismo, mutações em regiões não codificantes, deleções, rearranjos e casos atípicos podem estar contribuindo para a baixa freqüência de mutações identificadas. Esquizencefalia e polimicrogiria parecem não ter base genética relacionada com o gene EMX2. Um novo locus candidato em Xq27.2-Xq27.3 foi identificado para polimicrogiria perisylviana familiar.

OBJECTIVES: Malformations of cerebral cortex (MCC) are an important cause of epilepsy. Our main goals were: to search for mutations in genes responsible for MCC (FLN1, LIS1, DCX and EMX2), to map the locus for familial perisylvian polymicrogyria and to investigate the molecular mechanisms of the mutations identified. Methods: Mutation screening was performed by PCR, DHPLC and sequencing. HUMARA and Real Time PCR were performed to study the molecular mechanisms of mutations. Linkage analysis was carried out by PCR, Fragment profiler® and MLINK® software. RESULTS: Deleterious mutations were identified in 3/108 patients. We found a G987C splicing mutation in the FLN1 in two related patients with periventricular nodular heterotopia. Skewed X-chromosome inactivation was detected as the possible mechanism responsible for clinical differences observed in the two patients. An A1385C transversion (H277P) in LIS1 was identified in one patient with lisencephaly. Only neutral variants were identified in DCX and EMX2. Linkage analysis has detected a locus in Xq27.2-Xq27.3 for familial polymicrogyria. CONCLUSION: We believe that the low frequency of mutations identified may be due to mosaicism, mutations in non-coding regions, deletions and patients with atypical neuroimaging findings. Deleterious mutations in EMX2 were not found in patients with schizencephaly and polymicrogyria. We found a locus for familial perisylvian polymicrogyria in Xq27.2-Xq27.3.

Canais de potássio voltagem-dependentes (CPVD) desempenham importante papel na excitabilidade neuronal e estão associados a determinados tipos de epilepsia. Recentemente, um tipo de encefalite límbica autoimune (EL) foi associado com anticorpos contra CPVD. Além disso, há relatos de pacientes com EL e epilepsia parcial, além de hipersinal em regiões límbicas detectadas em imagens de ressonância magnética (IRM). Nós temos descrito a epilepsia de lobo temporal mesial familial (ELTMF) associada à atrofia hipocampal (AH) e outros sinais de esclerose mesial temporal observadas em IRM. Para investigar se os CPVD podem estar associados com a AH identificada na ELTMF, empregamos o estudo de ligação genética nesses genes candidatos. Setenta e três marcadores microssatélites foram genotipados e o LOD score de dois pontos mostrou Zmax variando de 0.11 a -9.53 para teta=0.00. No presente estudo, os dados obtidos com a análise de ligação mostram que os CPVD não estão envolvidos na determinação da AH na ELTMF.

Voltage-gated potassium channels (VGKCs) play a critical role in the regulation of neuronal excitability and have been implicated in some types of epilepsies. Recently, autoimmune limbic encephalitis (LE) was associated with antibodies against VGKC. In addition, patients with LE showed partial epilepsy and increased T2 signal abnormalities in limbic structures. We have reported familial mesial temporal lobe epilepsy (FMTLE) associated with hippocampal atrophy (HA) and other signs of mesial temporal sclerosis detected by magnetic resonance imaging (MRI). In order to investigate whether VGKC may be associated to HA present in FMTLE, we perform linkage study in these candidate genes. Seventy-three microsatellites markers were genotyped in different human autosomal chromosome. Two-point LOD scores did not show evidence for linkage with any of the microsatellite markers genotyped (Zmax ranging from 0.11to-9.53 at theta=0.00). In the present study, linkage data showed no evidence that VGKC are involved in the determination of HA in FMTLE.

The RNA interference (RNAi) technique is a recent technology that uses double-stranded RNA molecules to promote potent and specific gene silencing. The application of this technique to molecular biology has increased considerably, from gene function identification to disease treatment. However, not all small interfering RNAs (siRNAs) are equally efficient, making target selection an essential procedure. Here we present Strand Analysis (SA), a free online software tool able to identify and classify the best RNAi targets based on Gibbs free energy (deltaG). Furthermore, particular features of the software, such as the free energy landscape and deltaG gradient, may be used to shed light on RNA-induced silencing complex (RISC) activity and RNAi mechanisms, which makes the SA software a distinct and innovative tool.