Gene expression profile suggests different mechanisms underlying sporadic and familial mesial temporal lobe epilepsy.

Most patients with pharmacoresistant mesial temporal lobe epilepsy (MTLE) have hippocampal sclerosis on the postoperative histopathological examination. Although most patients with MTLE do not refer to a family history of the disease, familial forms of MTLE have been reported. We studied surgical specimens from patients with MTLE who had epilepsy surgery for medically intractable seizures. We assessed and compared gene expression profiles of the tissue lesion found in patients with familial MTLE (n = 3) and sporadic MTLE (n = 5). In addition, we used data from control hippocampi obtained from a public database (n = 7). We obtained expression profiles using the Human Genome U133 Plus 2.0 (Affymetrix) microarray platform. Overall, the molecular profile identified in familial MTLE differed from that in sporadic MTLE. In the tissue of patients with familial MTLE, we found an over-representation of the biological pathways related to protein response, mRNA processing, and synaptic plasticity and function. In sporadic MTLE, the gene expression profile suggests that the inflammatory response is highly activated. In addition, we found enrichment of gene sets involved in inflammatory cytokines and mediators and chemokine receptor pathways in both groups. However, in sporadic MTLE, we also found enrichment of epidermal growth factor signaling, prostaglandin synthesis and regulation, and microglia pathogen phagocytosis pathways. Furthermore, based on the gene expression signatures, we identified different potential compounds to treat patients with familial and sporadic MTLE. To our knowledge, this is the first study assessing the mRNA profile in surgical tissue obtained from patients with familial MTLE and comparing it with sporadic MTLE. Our results clearly show that, despite phenotypic similarities, both forms of MTLE present distinct molecular signatures, thus suggesting different underlying molecular mechanisms that may require distinct therapeutic approaches.

Multi-omic strategies applied to the study of pharmacoresistance in mesial temporal lobe epilepsy.

Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adults, and hippocampal sclerosis (HS) is a frequent histopathological feature in patients with MTLE. Pharmacoresistance is present in at least one-third of patients with MTLE with HS (MTLE+HS). Several hypotheses have been proposed to explain the mechanisms of pharmacoresistance in epilepsy, including the effect of genetic and molecular factors. In recent years, the increased knowledge generated by high-throughput omic technologies has significantly improved the power of molecular genetic studies to discover new mechanisms leading to disease and response to treatment. In this review, we present and discuss the contribution of different omic modalities to understand the basic mechanisms determining pharmacoresistance in patients with MTLE+HS. We provide an overview and a critical discussion of the findings, limitations, new approaches, and future directions of these studies to improve the understanding of pharmacoresistance in MTLE+HS. However, it is important to point out that, as with other complex traits, pharmacoresistance to anti-seizure medications is likely a multifactorial condition in which gene-gene and gene-environment interactions play an important role. Thus, studies using multidimensional approaches are more likely to unravel these intricate biological processes.

Multi-omics in mesial temporal lobe epilepsy with hippocampal sclerosis: Clues into the underlying mechanisms leading to disease.

Mesial temporal lobe epilepsy (MTLE) is one of the most common types of focal epilepsy in the adult population. MTLE is frequently associated with a specific histopathological lesion in the medial temporal structures, namely hippocampal sclerosis (HS). A significant proportion of patients with MTLE+HS have severe epilepsy, which is often resistant to clinical treatment. For these patients, surgical resection of the epileptogenic lesion can be performed. Our understanding of the underlying mechanisms leading to MTLE+HS has improved significantly over the past few decades. In this review, we aim to present and discuss the most recent findings regarding the genetic determinants of MTLE+HS. Furthermore, we will address studies about transcriptomics, proteomics, metabolomics, and epigenomic signatures of the tissue that is surgically removed from patients with refractory MTLE+HS and animal models of the disorder. We expect to provide an overview and a critical discussion of the findings, limitations, new approaches, and future directions for multi-omics studies in MTLE+HS.

Identification of environmental and genetic factors that influence warfarin time in therapeutic range.

Warfarin is an oral anticoagulant prescribed to prevent and treat thromboembolic disorders. It has a narrow therapeutic window and must have its effect controlled. Prothrombin test, expressed in INR value, is used for dose management. Time in therapeutic range (TTR) is an important outcome of quality control of anticoagulation therapy and is influenced by several factors. The aim of this study was to identify genetic, demographic, and clinical factors that can potentially influence TTR. In total,422 patients using warfarin were investigated. Glibenclamide co-medication and presence of CYP2C9*2 and/or *3 alleles were associated with higher TTR, while amiodarone, acetaminophen and verapamil co-medication were associated with lower TTR. Our data suggest that TTR is influenced by co-medication and genetic factors. Thus, individuals in use of glibenclamide may need a more careful monitoring and genetic testing (CYP2C9*2 and/or *3 alleles) may improve the anticoagulation management. In addition, in order to reach and maintain the INR in the target for a longer period, it is better to discuss dose adjustment in office instead of by telephone assessment. Other studies are needed to confirm these results and to find more variables that could contribute to this important parameter.

GAD1 gene polymorphisms are associated with hyperactivity in Attention-Deficit/Hyperactivity Disorder.

Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood. Recent studies suggest a role for γ-aminobutyric acid (GABA) on ADHD hyperactive/impulsive symptoms due to behavioral disinhibition resulting from inappropriate modulation of both glutamatergic and GABAergic signaling. The glutamic acid decarboxylase (GAD1) gene encodes a key enzyme of GABA biosynthesis. The aim of the present study was to investigate the possible influence of GAD1 SNPs rs3749034 and rs11542313 on ADHD susceptibility. The clinical sample consisted of 547 families with ADHD probands recruited at the ADHD Outpatient Clinics from Hospital de Clínicas de Porto Alegre. Hyperactive/impulsive symptoms were evaluated based on parent reports from the Swanson, Nolan, and Pelham Scale-version IV (SNAP-IV). The C allele of rs11542313 was significantly overtransmitted from parents to ADHD probands (P = 0.02). Hyperactive/impulsive score was higher in rs3749034G allele (P = 0.005, Cohen's D = 0.19) and rs11542313C allele (P = 0.03; Cohen's D = 0.16) carriers. GAD1 haplotypes were also associated with higher hyperactive/impulsive scores in ADHD youths (global P-value = 0.01). In the specific haplotype test, the GC haplotype was the one with the highest hyperactive/impulsive scores (P = 0.03). Our results suggest that the GAD1 gene is associated with ADHD susceptibility, contributing particularly to the hyperactive/impulsive symptom domain. © 2016 Wiley Periodicals, Inc.

The role of protein intrinsic disorder in major psychiatric disorders.

Although new candidate genes for Autism Spectrum Disorder (ASD), Schizophrenia (SCZ), Attention-Deficit/Hyperactivity Disorder (ADHD), and Bipolar Disorder (BD) emerged from genome-wide association studies (GWAS), their underlying molecular mechanisms remain poorly understood. Evidences of the involvement of intrinsically disordered proteins in diseases have grown in the last decade. These proteins lack tridimensional structure under physiological conditions and are involved in important cellular functions such as signaling, recognition and regulation. The aim of the present study was to identify the role and abundance of intrinsically disordered proteins in a set of psychiatric diseases and to test whether diseases are different regarding protein intrinsic disorder. Our hypothesis is that differences across psychiatric illnesses phenotypes and symptoms may arise from differences in intrinsic protein disorder content and properties of each group. A bioinformatics prediction of intrinsic disorder was performed in proteins retrieved based on top findings from GWAS, Copy Number Variation and candidate gene investigations for each disease. This approach revealed that about 80% of studied proteins presented long stretches of disorder. This amount was significantly higher than that observed in general eukaryotic proteins, and those involved in cardiovascular diseases. These results suggest that proteins with intrinsic disorder are a common feature of neurodevelopment and synaptic transmission processes which are potentially involved in the etiology of psychiatric diseases. Moreover, we identified differences between ADHD and ASD when the binary prediction of structure and putative binding sites were compared. These differences may be related to variation in symptom complexity between both diseases. © 2016 Wiley Periodicals, Inc.

NOS1 and SNAP25 polymorphisms are associated with Attention-Deficit/Hyperactivity Disorder symptoms in adults but not in children.

Several investigations documented that Attention-Deficit/Hyperactivity Disorder (ADHD) is better conceptualized as a dimensional disorder. At the same time, the disorder seems to have different neurobiological underpinnings and phenotypic presentation in children compared to adults. Neurodevelopmental genes could explain, at least partly these differences. The aim of the present study was to examine possible associations between polymorphisms in SNAP25, MAP1B and NOS1 genes and ADHD symptoms in Brazilian samples of children/adolescents and adults with ADHD. The youth sample consisted of 301 patients whereas the adult sample comprises 485 individuals with ADHD. Diagnoses of ADHD and comorbidities were based on the Diagnostic and Statistical Manual of Mental Disorders-4th edition criteria. The Swanson, Nolan and Pelham Scale-Version IV (SNAP-IV) was applied by psychiatrists blinded to genotype. The total SNAP-IV scores were compared between genotypes. Impulsivity SNAP-IV scores were also compared according to NOS1 genotypes. Adult patients homozygous for the C allele at SNAP25 rs8636 showed significantly higher total SNAP-IV scores (F = 11.215; adjusted P-value = 0.004). Impulsivity SNAP-IV scores were also significantly different according to NOS1 rs478597 polymorphisms in adults with ADHD (F = 6.282; adjusted P-value = 0.026). These associations were not observed in children and adolescents with ADHD. These results suggest that SNAP25 and NOS1 genotypes influence ADHD symptoms only in adults with ADHD. Our study corroborates previous evidences for differences in the genetic contribution to adult ADHD compared with childhood ADHD.

MAP1B and NOS1 genes are associated with working memory in youths with attention-deficit/hyperactivity disorder.

Diverse efforts have been done to improve the etiologic understanding of mental disorders, such as attention-deficit/hyperactivity disorder (ADHD). It becomes clear that research in mental disorders needs to move beyond descriptive syndromes. Several studies support recent theoretical models implicating working memory (WM) deficits in ADHD complex neuropsychology. The aim of this study was to examine the association between rs2199161 and rs478597 polymorphisms at MAP1B and NOS1 genes with verbal working memory in children and adolescents with ADHD. A total of 253 unrelated ADHD children/adolescents were included. The sample was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders-4th edition criteria. Digit Span from the Wechsler Intelligence Scale for Children-Third Edition was used to assess verbal WM. The raw scores from both forward and backward conditions of Digit Span were summed and converted into scaled scores according to age. The means of scaled Digit Span were compared according to genotypes by ANOVA. Significant differences in Digit Span scores between MAP1B genotype groups (rs2199161: F = 5.676; p = 0.018) and NOS1 (rs478597: F = 6.833; p = 0.009) genes were detected. For both polymorphisms, the CC genotype carriers showed a worse performance in WM task. Our findings suggest possible roles of NOS1 and MAP1B genes in WM performance in ADHD patients, replicating previous results with NOS1 gene in this cognitive domain in ADHD children.

Impact of population diversity on the prediction of 7-SNP NAT2 phenotypes using the tagSNP rs1495741 or paired SNPs.

A novel NAT2 tagSNP (rs1495741) and a 2-SNP genotype (rs1041983 and rs1801280) have been recently shown to accurately predict the NAT2 acetylator phenotypes in populations of exclusive or predominant European/White ancestry. We confirmed the accuracy of the tagSNP approach in White Brazilians, but not in Brown or Black Brazilians, sub-Saharan Mozambicans, and Guarani Amerindians. The combined rs1041983 and rs1801280 genotypes provided considerably better prediction of the NAT2 phenotype in Guarani, but no consistent improvement in Brown or Black Brazilians and Mozambicans. Best predictions of the NAT2 phenotype in Mozambicans using NAT2 SNP pairs were obtained with rs1801280 and rs1799930, but the accuracy of the estimates remained inadequate for clinical use or for investigations in this sub-Saharan group or in Brazilians with considerable African ancestry. In conclusion, the rs1495741 tagSNP cannot be applied to predict the NAT2 acetylation phenotype in Guarani and African-derived populations, whereas 2-SNP genotypes may accurately predict NAT2 phenotypes in Guarani, but not in Africans.