De novo gain of function mutations in GRIN2B encoding the GluN2B subunit of the N-methyl-d-aspartate (NMDA) receptor have been linked with epileptic encephalopathies, including infantile spasms. We investigated the effects of radiprodil, a selective GluN2B negative allosteric modulator and other non-selective NMDA receptor inhibitors on glutamate currents mediated by NMDA receptors containing mutated GluN2B subunits. The experiments were performed in Xenopus oocytes co-injected with the following human mRNAs: GRIN1/GRIN2B, GRIN1/GRIN2B-R540H, GRIN1/GRIN2B-N615I and GRIN1/GRIN2B-V618G. Glutamate displayed slightly increased potency in the R540H variant, but not in N615I and V618G variants. However, the inhibition by Mg2+ was completely abolished in N615I and V618G variants. In fact, Mg2+ enhanced glutamate responses in those variants. The potency of radiprodil to block glutamate-evoked currents was not affected in any of the variants, while the effects by non-selective NMDA inhibitors were greatly reduced in some of the variants. Additionally, in the Mg2+ insensitive variants, radiprodil blocked glutamate-activated currents with the same potency as in the absence of Mg2+. The gain of function observed in the reported GRIN2B variants could be a key pathophysiological factor leading to neuronal hyper-excitability in epileptic encephalopathies. The GluN2B-selective inhibitor radiprodil fully retained its pharmacological profile under these conditions, while other non-selective NMDA receptor antagonists lost their potency. Consequently, our data suggest that radiprodil may be a valuable therapeutic option for treatment of pediatric epileptic encephalopathies associated with GRIN2B mutations.

Tuberous sclerosis complex (TSC) is characterized by hamartomatous lesions in various organs and arises due to mutations in the TSC1 or TSC2 genes. TSC mutations lead to a range of neurological manifestations including epilepsy, cognitive impairment, autism spectrum disorders (ASD), and brain lesions that include cortical tubers. There is evidence that seizures arise at or near cortical tubers, but it is unknown why some tubers are epileptogenic while others are not. We have previously reported increased tryptophan metabolism measured with α[11C]-methyl-l-tryptophan (AMT) positron emission tomography (PET) in epileptogenic tubers in approximately two-thirds of patients with tuberous sclerosis and intractable epilepsy. However, the underlying mechanisms leading to seizure onset in TSC remain poorly characterized. MicroRNAs are enriched in the brain and play important roles in neurodevelopment and brain function. Recent reports have shown aberrant microRNA expression in epilepsy and TSC. In this study, we performed microRNA expression profiling in brain specimens obtained from TSC patients undergoing epilepsy surgery for intractable epilepsy. Typically, in these resections several non-seizure onset tubers are resected together with the seizure-onset tubers because of their proximity. We directly compared seizure onset tubers, with and without increased tryptophan metabolism measured with PET, and non-onset tubers to assess the role of microRNAs in epileptogenesis associated with these lesions. Whether a particular tuber was epileptogenic or non-epileptogenic was determined with intracranial electrocorticography, and tryptophan metabolism was measured with AMT PET. We identified a set of five microRNAs (miR-142-3p, 142-5p, 223-3p, 200b-3p and 32-5p) that collectively distinguish among the three primary groups of tubers: non-onset/AMT-cold (NC), onset/AMT-cold (OC), and onset/AMT-hot (OH). These microRNAs were significantly upregulated in OH tubers compared to the other two groups, and microRNA expression was most significantly associated with AMT-PET uptake. The microRNAs target a group of genes enriched for synaptic signaling and epilepsy risk, including SLC12A5, SYT1, GRIN2A, GRIN2B, KCNB1, SCN2A, TSC1, and MEF2C. We confirmed the interaction between miR-32-5p and SLC12A5 using a luciferase reporter assay. Our findings provide a new avenue for subsequent mechanistic studies of tuber epileptogenesis in TSC.

Degenerative lumbar scoliosis (DLS) progresses with aging after 50-60 years. The genetic association of DLS remains largely unclear. In this study, the genetic association between glutamate receptor, ionotropic, N-methyl D-aspartate (NMDA, GRIN) receptor genes and DLS was investigated. A total of 9 coding single nucleotide polymorphisms (cSNPs) in NMDA receptor genes [GRIN2A (rs8049651, Leu425Leu; rs9806806, Tyr730Tyr); GRIN2B (rs7301328, Pro122Pro; rs35025065, Asp447Asp; rs1805522, Ile602Ile; rs1806201, Thr888Thr; rs1805247, His1399His); and GRIN2C (rs689730, Ala33Ala; rs3744215, Arg1209Ser)] were selected and genotyped using direct sequencing in 70 patients with DLS and 141 healthy controls. Multiple logistic models (codominant, dominant and recessive) were calculated for the odds ratio (OR), 95% confidence interval (CI) and corresponding P-values. The SNPStats, SNPAnalyzer and HelixTree programs were used for the evaluation of the genetic data. Among the SNPs examined, no significant associations were observed between the NMDA receptor genes and DLS. When the patients were divided into two groups according to clinical characteristics based on Cobb's angle (<20° or ≥20°) and lateral listhesis (<6 mm or ≥6 mm), associations were observed between rs689730 of GRIN2C and Cobb's angle (codominant, P=0.038; dominant, P=0.022) and between rs7301328 of GRIN2B and lateral listhesis (codominant, P=0.003; dominant, P=0.015; recessive, P=0.015). These results indicate that the GRIN2A, GRIN2B and GRIN2C genes do not affect the development of DLS. However, the GRIN2C gene may be associated with Cobb's angle, while the GRIN2B gene may be associated with lateral listhesis.

Abnormalities in glutamate signaling and glutamate toxicity are thought to be important in the pathophysiology of bipolar disorder (BD). Whilst previous studies have found brain white matter changes in BD, there is paucity of data about how glutamatergic genes affect brain white matter integrity in BD. Based on extant neuroimaging data, we hypothesized that GRIN2B risk allele is associated with reductions of brain white matter integrity in the frontal, parietal, temporal, and occipital regions and cingulate gyrus in BD. Fourteen patients with BD and 22 healthy controls matched in terms of age, gender and handedness were genotyped using blood samples and underwent diffusion tensor imaging. Compared to G allele, brain FA values were significantly lower in BD patients with risk T allele in left frontal region (P = 0.001), right frontal region (P = 0.002), left parietal region (P = 0.001), left occipital region (P = 0.001), right occipital region (P < 0.001), and left cingulate gyrus (P = 0.001). Further elucidation of the interactions between different glutamate genes and their relationships with such structural, functional brain substrates will enhance our understanding of the link between dysregulated glutamatergic neurotransmission and neuroimaging endophenotypes in BD.

Suicidal behavior (SB) has a complex etiology involving different polygenic and environmental components. Here we used an excess of significant markers (ESM) test to study gene-level associations in previous genome-wide association studies (GWAS) SNP data from a family-based sample, having medically severe suicide attempt (SA) as main outcome in the offspring. In SA without major psychiatric disorders (N = 498), a screening of 5,316 genes across the genome suggested association 17 genes (at fdr < 0.05). Genes RETREG1 (a.k.a. FAM134B), GSN, GNAS, and CACNA1D were particularly robust to different methodological variations. Comparison with the more widely used Multi-marker Analysis of GenoMic Annotation (MAGMA) methods, mainly supported RETREG1, GSN, RNASEH2B, UBE2H, and CACNA1D by using the "mean" model, and ranked 13 of the same genes as ESM among its top-17. Complementing the ESM screen by using MAGMA to analyze 17,899 genes, we observed excess of genes with p < .05 by using the "top" model, and the "mean" model suggested additional genes with genome-wide fdr < 0.25. Overrepresentation analysis of 10 selected gene sets using all genes with p < .05, showed significant results for synaptic genes, genes differentially expressed in brain development and for ~12% of the SA polygenic association genes identified previously in this sample. Exploratory analysis linked some of the ESM top-17 genes to psychotropic drugs and we examined the allelic heterogeneity in the previous SA candidate GRIN2B. This study complemented previous GWAS on SB outcomes, implicating both previous candidate (e.g., GRIN2B and GNAS) and novel genes in SA outcomes, as well as synaptic functions and brain development.

Even if substantial heritability has been reported and candidate genes have been identified extensively, all known marker associations explain only a small proportion of the phenotypic variance of developmental dyslexia (DD) and related quantitative phenotypes. Gene-by-gene interaction (also known as "epistasis"--G × G) triggers a non-additive effect of genes at different loci and should be taken into account in explaining part of the missing heritability of this complex trait. We assessed potential G × G interactions among five DD candidate genes, i.e., DYX1C1, DCDC2, KIAA0319, ROBO1, and GRIN2B, upon DD-related neuropsychological phenotypes in 493 nuclear families with DD, by implementing two complementary regression-based approaches: (1) a general linear model equation whereby the trait is predicted by the main effect of the number of rare alleles of the two genes and by the effect of the interaction between them, and (2) a family-based association test to detect G × G interactions between two unlinked markers by splitting up the association effect into a between- and a within-family genetic orthogonal components. After applying 500,000 permutations and correcting for multiple testing, both methods show that G × G effects between markers within the DYX1C1, KIAA0319/TTRAP, and GRIN2B genes lower the memory letters composite z-score of on average 0.55 standard deviation. We provided initial evidence that the effects of familial transmission of synergistic interactions between genetic risk variants can be exploited in the study of the etiology of DD, explain part of its missing heritability, and assist in designing customized charts of individualized neurocognitive impairments in complex disorders, such as DD.

Considerable evidence has suggested that the epigenetic regulation of N-methyl-D-aspartate (NMDA) glutamate receptors plays a crucial role in neuropsychiatric disorders. Previous exploratory studies have been primarily based on evidence from patients and have rarely sampled the general population. This exploratory study examined the relationship of single-nucleotide polymorphism (SNP) variations in the genes encoding the NMDA receptor (i.e., GRIN1, GRIN2A, GRIN2B, GRIN2C, and GRIN2D) with emotion and social behavior in adolescents. For this study, 832 tenth-grade Taiwanese volunteers were recruited, and their scores from the Beck Youth Inventories were used to evaluate their emotional and social impairments. Based on these scores, GRIN1 (rs4880213) was significantly associated with depression and disruptive behavior. In addition, GRIN2B (rs7301328) was significantly associated with disruptive behavior. Because emotional and social impairment greatly influence learning ability, the findings of this study provide important information for clinical treatment and the development of promising prevention and treatment strategies, especially in the area of psychological adjustment.

The corticostriatal pathway that carries sensory, motor, and limbic information to the striatum plays a critical role in motor control, action selection, and reward. Dysfunction of this pathway is associated with many neurological and psychiatric disorders. Corticostriatal synapses have unique features in their cortical origins and striatal targets. In this review, we first describe axonal growth and synaptogenesis in the corticostriatal pathway during development, and then summarize the current understanding of the molecular bases of synaptic transmission and plasticity at mature corticostriatal synapses. Genes associated with autism spectrum disorder (ASD) have been implicated in axonal growth abnormalities, imbalance of the synaptic excitation/inhibition ratio, and altered long-term synaptic plasticity in the corticostriatal pathway. Here, we review a number of ASD-associated high-confidence genes, including FMR1, KMT2A, GRIN2B, SCN2A, NLGN1, NLGN3, MET, CNTNAP2, FOXP2, TSHZ3, SHANK3, PTEN, CHD8, MECP2, DYRK1A, RELN, FOXP1, SYNGAP1, and NRXN, and discuss their relevance to proper corticostriatal function.

Several pieces of evidence showed that N-methyl D-aspartate (NMDA)-receptor-mediated decreases in function may be a causative factor for schizophrenia. The NMDA receptors are composed of a common glutamate receptor, an ionotropic NMDA 1 (GRIN1) subunit and one of four GRIN2 subunits (GRIN2A-GRIN2D), combined in an undetermined ratio to make up the receptor complex. In this study, we tested the hypothesis of whether the GRIN2B 366C/G and 2664C/T genetic polymorphisms are related to Chinese treatment-refractory schizophrenic patients. 193 treatment-refractory schizophrenic patients and 176 normal subjects were recruited for this study. The results demonstrated that the genotype distribution was similar between schizophrenic patients and control subjects in 366C/G (p = 0.88) and 2664C/T (p = 0.336), but we found a higher mean clozapine dosage in 2664C/C genotype patients. These results show that GRIN2B genetic variations were not a major risk factor for treatment-refractory schizophrenic patients, but may influence the effect of clozapine during treatment.

Opiates, one of the oldest known drugs, are the benchmark for treating pain. Regular opioid exposure also induces euphoria making these compounds addictive and often misused, as shown by the current epidemic of opioid abuse and overdose mortalities. In addition to the effect of opioids on their cognate receptors and signaling cascades, these compounds also induce multiple adaptations at cellular and behavioral levels. As omega-3 polyunsaturated fatty acids (n-3 PUFAs) play a ubiquitous role in behavioral and cellular processes, we proposed that supplemental n-3 PUFAs, enriched in docosahexanoic acid (DHA), could offset these adaptations following chronic opioid exposure. We used an 8 week regimen of n-3 PUFA supplementation followed by 8 days of morphine in the presence of this diet. We first assessed the effect of morphine in different behavioral measures and found that morphine increased anxiety and reduced wheel-running behavior. These effects were reduced by dietary n-3 PUFAs without affecting morphine-induced analgesia or hyperlocomotion, known effects of this opiate acting at mu opioid receptors. At the cellular level we found that morphine reduced striatal DHA content and that this was reversed by supplemental n-3 PUFAs. Chronic morphine also increased glutamatergic plasticity and the proportion of Grin2B-NMDARs in striatal projection neurons. This effect was similarly reversed by supplemental n-3 PUFAs. Gene analysis showed that supplemental PUFAs offset the effect of morphine on genes found in neurons of the dopamine receptor 2 (D2)-enriched indirect pathway but not of genes found in dopamine receptor 1(D1)-enriched direct-pathway neurons. Analysis of the D2 striatal connectome by a retrogradely transported pseudorabies virus showed that n-3 PUFA supplementation reversed the effect of chronic morphine on the innervation of D2 neurons by the dorsomedial prefontal and piriform cortices. Together these changes outline specific behavioral and cellular effects of morphine that can be reduced or reversed by dietary n-3 PUFAs.

Maternal over-nutrition may predispose offspring to obesity, type 2 diabetes and other adult diseases. The present study investigated long-term impact of prenatal high sucrose (HS) diets on cognitive capabilities in aged rat offspring. The fasting plasma glucose concentration did not differ between the control and HS groups. However, the fasting plasma insulin and insulin resistance index values were significantly increased in HS offspring that showed abnormal glucose tolerance test. HS offspring exhibited increased escape latency and swimming path length to the platform, and reduced time in the target quadrant and the number of crossing the platform, as compared with the control group. The expression of Grin2b/NR2B, Wnt2, Wnt3a and active form of β-catenin protein were decreased, and Dickkopf-related protein 1 was increased in the HS group. In addition, the levels of lipid peroxidation biomarker thiobarbituricacid reactive substance, nicotinamide adenine dinucleotide phosphate oxidases 2 and superoxide dismutase 1 were significantly increased, and the activity of catalase was decreased in the hippocampus in the HS group. The results demonstrate that prenatal HS-induced metabolic changes cause cognitive deficits in aged rat offspring, probably due to altered N-methyl-d-aspartate receptors/Wnt signaling and oxidative stress in the hippocampus.

Prenatal exposure to polycyclic aromatic hydrocarbons (PAH) has been associated with sustained effects on the brain and behavior in offspring. However, the mechanisms have yet to be determined. We hypothesized that prenatal exposure to ambient PAH in mice would be associated with impaired neurocognition, increased anxiety, altered cortical expression of Bdnf and Grin2b, and greater DNA methylation of Bdnf. Our results indicated that during open-field testing, prenatal PAH exposed offspring spent more time immobile and less time exploring. Females produced more fecal boli. Offspring prenatally exposed to PAH displayed modest reductions in overall exploration of objects. Further, prenatal PAH exposure was associated with lower cortical expression of Grin2b and Bdnf in males, and greater Bdnf IV promoter methylation. Epigenetic differences within the Bdnf IV promoter correlated with Bdnf gene expression, but not with the observed behavioral outcomes, suggesting that additional targets may account for these PAH-associated effects.

Artificial light at night induces circadian disruptions and causes cognitive impairment and mood disorders; yet very little is known about the neural and molecular correlates of these effects in diurnal animals. We manipulated the night environment and examined cellular and molecular changes in hippocampus, the brain region involved in cognition and mood, of Indian house crows (Corvus splendens) exposed to 12 hr light (150 lux): 12 hr darkness (0 lux). Diurnal corvids are an ideal model species with cognitive abilities at par with mammals. Dim light (6 lux) at night (dLAN) altered daily activity:rest pattern, reduced sleep, and induced depressive-like responses (decreased eating and self-grooming, self-mutilation, and reduced novel object exploration); return to an absolute dark night reversed these negative effects. dLAN suppressed nocturnal melatonin levels; however, diurnal corticosterone levels were unaffected. Concomitant reduction of immunoreactivity for DCX and BDNF suggested dLAN-induced suppression of hippocampal neurogenesis and compromised neuronal health. dLAN also negatively influenced hippocampal expression of genes associated with depressive-like responses (bdnf, il-1β, tnfr1, nr4a2), but not of those associated with neuronal plasticity (egr1, creb, syngap, syn2, grin2a, grin2b), cellular oxidative stress (gst, sod3, cat1) and neuronal death (caspase2, caspase3, foxo3). Furthermore, we envisaged the role of BDNF and showed epigenetic modification of bdnf gene by decreased histone H3 acetylation and increased hdac4 expression under dLAN. These results demonstrate transcriptional and epigenetic bases of dLAN-induced negative effects in diurnal crows, and provide insights into the risks of exposure to illuminated nights to animals including humans in an urban setting.

Helicobacter pylori (H. pylori) is well-known to be involved in gastric carcinogenesis, associated with deregulation of cell proliferation and epigenetic changes in cancer-related genes. H. pylori infection is largely acquired during childhood, persisting long-term in about half of infected individuals, a subset of whom will go on to develop peptic ulcer disease and eventually gastric cancer, however, the sequence of events leading to disease is not completely understood. Knowledge on carcinogenesis and gastric damage-related biomarkers is abundant in adult populations, but scarce in children. We performed an extensive literature review focusing on gastric cancer related biomarkers identified in adult populations, which have been detected in children infected with H. pylori. Biomarkers were related to expression levels (RNA or protein) and/or methylation levels (DNA) in gastric tissue or blood of infected children as compared to non-infected controls. In this review, we identified 37 biomarkers of which 24 are over expressed, three are under expressed, and ten genes are significantly hypermethylated in H. pylori-infected children compared to healthy controls in at least 1 study. Only four of these biomarkers (pepsinogen I, pepsinogen II, gastrin, and SLC5A8) have been studied in asymptomatically infected children. Importantly, 13 of these biomarkers (β-catenin, C-MYC, GATA-4, DAPK1, CXCL13, DC-SIGN, TIMP3, EGFR, GRIN2B, PIM2, SLC5A8, CDH1, and VCAM-1.) are consistently deregulated in infected children and in adults with gastric cancer. Future studies should be designed to determine the clinical significance of these changes in infection-associated biomarkers in children and their persistence over time. The effect of eradication therapy over these biomarkers in children if proven significant, could lead to modifications in treatment guidelines for younger populations, and eventually promote the development of preventive strategies, such as vaccination, in the near future.

N-methyl-d-aspartate receptors (NMDARs) play a critical role in excitatory synaptic transmission and plasticity in the central nervous systems. Recent genetics studies in schizophrenia (SCZ) show that SCZ is susceptible to NMDARs and the NMDAR signaling complex. In autism spectrum disorder (ASD), several studies report dysregulation of NMDARs as a risk factor for ASD. To further examine the association between NMDARs and SCZ/ASD development, we conducted a mutation screening study of GRIN2B which encodes NR2B subunit of NMDARs, to identify rare mutations that potentially cause diseases, in SCZ and ASD patients (n = 574 and 152, respectively). This was followed by an association study in a large sample set of SCZ, ASD, and normal healthy controls (n = 4145, 381, and 4432, respectively). We identified five rare missense mutations through the mutation screening of GRIN2B. Although no statistically significant association between any single mutation and SCZ or ASD was found, one of its variant, K1292R, is found only in the patient group. To further examine the association between mutations in GRIN2B and SCZ/ASD development, a larger sample size and functional experiments are needed.

Traditional pharmacological approaches to the treatment of obsessive-compulsive disorder (OCD) are based on affecting serotonergic and dopaminergic transmission in the central nervous system. However, genetic epidemiology findings are pointing to glutamate pathways and developmental genes as etiological in OCD. A review of recent genetic findings in OCD is conducted, and bioinformatics approaches are used to locate pathways relevant to neuroprotection. The OCD susceptibility genes DLGAP1, RYR3, PBX1-MEIS2, LMX1A and candidate genes BDNF and GRIN2B are components of the neuronal growth, differentiation and neurogenesis pathways BDNF-mTOR. These pathways are emerging as a promising area of research for the development of neuroprotective pharmaceuticals. Emergent genetic epidemiologic data on OCD and repetitive behaviors may support new approaches for pharmacological discovery. Neuroprotective approaches that take into consideration glutamate-mediated BDNF-mTOR pathways are suggested by OCD susceptibility genes.

The N-methyl-D-aspartate (NMDA) receptor channel is essential for synaptic transmission and synaptic plasticity underlying memory, learning, and development. Three subunits of the NMDA receptor channel, NMDAR2A, NMDAR2B, and NMDAR2C (NR2A, NR2B, and NR2C), previously identified in mouse by cDNA cloning and expression, share a high level of homology, although their patterns of expression within the brain may differ. In the present work we report the localization of the gene encoding the human NMDAR2B receptor subunit (called GRIN2B for glutamate receptor, ionotropic, N-methyl-D-aspartate 2B) to chromosome 12p12 by in situ hybridization and somatic cell hybrids.

Evidences have indicated a high degree of comorbidity of alcoholism and depression. N-acetylcysteine (NAC) has shown its clinical efficiency in the treatment of several psychiatric disorders and is identified as a multi-target acting drug. The ability of NAC to prevent alcohol abstinence-induced depression-like effects and underlying mechanism(s) have not been adequately addressed. This study was aimed to investigate the beneficial effects of NAC in the alcohol abstinence-induced depression developed following long-term voluntary alcohol intake. For evaluation of the effects of NAC, Sprague-Dawley rats were enabled to voluntary drinking of 4.5%, 7.5% and 9% v/v alcohol for fifteen days. NAC (25, 50, and 100 mg/kg) and fluoxetine (5 mg/kg) were injected intraperitoneally for three consecutive days during the alcohol abstinence period on the days 16, 17, 18. The behavioral studies were conducted employing forced swim test (FST), and tail suspension test (TST) on day 18 to determine the effects of N-acetylcysteine and fluoxetine in the ethanol withdrawal induced-depression. Blood alcohol concentration, alcohol biomarkers like SGPT, SGOT, ALP, GGT, and MCV were estimated by using commercially available kits. Serotonin concentrations were measured in the plasma, hippocampus and pre-frontal cortex using the rat ELISA kit. The expression of GRIN1, GRIN2A, GRIN2B genes for the N-methyl d-aspartate receptors (NMDAR) subunits in the hippocampus and the prefrontal cortex were also examined by reverse-transcription quantitative polymerase chain reaction. The results revealed that alcohol abstinence group depicted increased immobility time in FST and TST. Further, NAC exerted significant protective effect at the doses 50 mg/kg and 100 mg/kg, but 25 mg/kg showed insignificant protection against alcohol abstinence-induced depression. The increased level of biochemical parameters following ethanol abstinence were also reversed by NAC at the dose of 100 mg/kg. The significant reversal effect of NAC on the serotonin level following alcohol abstinence was greater in the hippocampus as compared to the third-day alcohol withdrawal group. The increased expression levels of GRIN2A and GRIN2B following ethanol abstinence were reversed with a higher dose of NAC (100 mg/kg) treatment. In conclusion, the results of the study reveal that NAC has remarkable protective effects in the alcohol abstinence-induced depression by modulating alcohol markers, serotonin levels and GRIN2A, GRIN2B gene expression of NMDAR signaling pathway in rats.

The duplication of the short arm (p) of chromosome 12 is a rare chromosomal abnormality, and most reported cases result from malsegregation of a balanced parental translocation associated with other chromosomal imbalances. Of the reported cases, only 15 involve a pure and complete 12p duplication and only 10 involve a pure and partial duplication overlapping the 12p12.3p13.1 region, including a single instance of an inherited duplication in two related individuals. Here, we report three new patients with a pure 12p duplication, detected by conventional cytogenetic studies and characterized by array-comparative genomic hybridization (array-CGH) and fluorescence in situ hybridization (FISH). The first patient was a child carrying a de novo inverted duplication of the short arm of chromosome 12. His phenotype was similar to that of the "trisomy 12p syndrome", characterized by developmental delays and craniofacial abnormalities including a high forehead, a short nose with anteverted nostrils and an everted lower lip. The second and third patients were a mother and son with a direct 12p12.3p13.1 duplication, exhibiting a milder phenotype characterized by moderate developmental delays, dysmorphic facial features, behavioral problems and obesity. The present data, including the rarity of the familial cases, should contribute to our knowledge of the genotype/phenotype correlation in trisomy 12p patients.

Genetic and bioinformatic analyses have identified missense mutations in GRIN2B encoding the NMDA receptor GluN2B subunit in autism, intellectual disability, Lennox Gastaut and West Syndromes. Here, we investigated several such mutations using a near-complete, hybrid 3D model of the human NMDAR and studied their consequences with kinetic modelling and electrophysiology. The mutants revealed reductions in glutamate potency; increased receptor desensitisation; and ablation of voltage-dependent Mg2+ block. In addition, we provide new views on Mg2+ and NMDA channel blocker binding sites. We demonstrate that these mutants have significant impact on excitatory transmission in developing neurons, revealing profound changes that could underlie their associated neurological disorders. Of note, the NMDAR channel mutant GluN2BV618G unusually allowed Mg2+ permeation, whereas nearby N615I reduced Ca2+ permeability. By identifying the binding site for an NMDAR antagonist that is used in the clinic to rescue gain-of-function phenotypes, we show that drug binding may be modified by some GluN2B disease-causing mutations.

Lead (Pb) is neurotoxic and children are highly susceptible to this effect, particularly within the context of continuous low-level Pb exposure. A current major challenge is identification of children who may be uniquely susceptible to Pb toxicity because of genetic predisposition. Learning and memory are among the neurobehavioral processes that are most notably affected by Pb exposure, and modification of N-methyl-D-aspartate receptors (NMDAR) that regulate these processes during development are postulated to underlie these adverse effects of Pb. We examined the hypothesis that polymorphic variants of genes encoding glutamate receptor, ionotropic, NMDAR subunits 2A and 2B, GRIN2A and GRIN2B, exacerbate the adverse effects of Pb exposure on these processes in children. Participants were subjects who participated as children in the Casa Pia Dental Amalgam Clinical Trial and for whom baseline blood Pb concentrations and annual neurobehavioral test results over the 7 year course of the clinical trial were available. Genotyping assays were performed for variants of GRIN2A (rs727605 and rs1070503) and GRIN2B (rs7301328 and rs1806201) on biological samples acquired from 330 of the original 507 trial participants. Regression modeling strategies were employed to evaluate the association between genotype status, Pb exposure, and neurobehavioral test outcomes. Numerous significant adverse interaction effects between variants of both GRIN2A and GRIN2B, individually and in combination, and Pb exposure were observed particularly among boys, preferentially within the domains of Learning & Memory and Executive Function. In contrast, very few interaction effects were observed among similarly genotyped girls with comparable Pb exposure. These findings support observations of an essential role of GRIN2A and GRIN2B on developmental processes underlying learning and memory as well as other neurological functions in children and demonstrate, further, modification of Pb effects on these processes by specific variants of both GRIN2A and GRIN2B genes. These observations highlight the importance of genetic factors in defining susceptibility to Pb neurotoxicity and may have important public health implications for future strategies aimed at protecting children and adolescents from potential health risks associated with low-level Pb exposure.

Background: A practical strategy to discover sepsis specific proteins may be to compare the plasma peptides and proteins from patients in the intensive care unit with and without sepsis. The aim was to discover proteins and/or peptides that show greater observation frequency and/or precursor intensity in sepsis. The endogenous tryptic peptides of ICU-Sepsis were compared to ICU Control, ovarian cancer, breast cancer, female normal, sepsis, heart attack, Alzheimer's and multiple sclerosis along with their institution-matched controls, female normals and normal samples collected directly onto ice.

Methods: Endogenous tryptic peptides were extracted from individual sepsis and control EDTA plasma samples in a step gradient of acetonitrile for random and independent sampling by LC-ESI-MS/MS with a set of robust and sensitive linear quadrupole ion traps. The MS/MS spectra were fit to fully tryptic peptides within proteins using the X!TANDEM algorithm. The protein observation frequency was counted using the SEQUEST algorithm after selecting the single best charge state and peptide sequence for each MS/MS spectra. The protein observation frequency of ICU-sepsis versus ICU Control was subsequently tested by Chi square analysis. The average protein or peptide log₁₀ precursor intensity was compared across disease and control treatments by ANOVA in the R statistical system.

Results: Peptides and/or phosphopeptides of common plasma proteins such as ITIH3, SAA2, SAA1, and FN1 showed increased observation frequency by Chi square (χ² > 9, p < 0.003) and/or precursor intensity in sepsis. Cellular gene symbols with large Chi square values from tryptic peptides included POTEB, CTNNA1, U2SURP, KIF24, NLGN2, KSR1, GTF2H1, KIT, RPS6KL1, VAV2, HSPA7, SMC2, TCEB3B, ZNF300, SUPV3L1, ADAMTS20, LAMB4, MCCC1, SUPT6H, SCN9A, SBNO1, EPHA1, ABLIM2, cB5E3.2, EPHA10, GRIN2B, HIVEP2, CCL16, TKT, LRP2 and TMF1 amongst others showed increased observation frequency. Similarly, increased frequency of tryptic phosphopeptides were observed from POM121C, SCN8A, TMED8, NSUN7, SLX4, MADD, DNLZ, PDE3B, UTY, DEPDC7, MTX1, MYO1E, RXRB, SYDE1, FN1, PUS7L, FYCO1, USP26, ACAP2, AHI1, KSR2, LMAN1, ZNF280D and SLC8A2 amongst others. Increases in mean precursor intensity in peptides from common plasma proteins such as ITIH3, SAA2, SAA1, and FN1 as well as cellular proteins such as COL24A1, POTEB, KANK1, SDCBP2, DNAH11, ADAMTS7, MLLT1, TTC21A, TSHR, SLX4, MTCH1, and PUS7L among others were associated with sepsis. The processing of SAA1 included the cleavage of the terminal peptide D/PNHFRPAGLPEKY from the most hydrophilic point of SAA1 on the COOH side of the cystatin C binding that was most apparent in ICU-Sepsis patients compared to all other diseases and controls. Additional cleavage of SAA1 on the NH2 terminus side of the cystatin binding site were observed in ICU-Sepsis. Thus there was disease associated variation in the processing of SAA1 in ICU-Sepsis versus ICU controls or other diseases and controls.

Conclusion: Specific proteins and peptides that vary between diseases might be discovered by the random and independent sampling of multiple disease and control plasma from different hospital and clinics by LC-ESI-MS/MS for storage in a relational SQL Server database and analysis with the R statistical system that will be a powerful tool for clinical research. The processing of SAA1 may play an unappreciated role in the inflammatory response to Sepsis.

Keywords: Chi square test and ANOVA; Discovery of variation; Electrospray ionization tandem mass spectrometry; Human EDTA plasma; Intensive Care Unit; LC–ESI–MS/MS; Linear quadrupole ion trap; Nano chromatography; Organic extraction; Random and independent sampling; SQL SERVER & R; Sepsis.