pubmed: autism and genetics

Subscribe to pubmed: autism and genetics feed pubmed: autism and genetics
NCBI: db=pubmed; Term=autism AND genetics
Updated: 16 min 22 sec ago

Altered tactile processing in children with autism spectrum disorder.

November 17, 2015 - 9:44am

Altered tactile processing in children with autism spectrum disorder.

Autism Res. 2015 Nov 16;

Authors: Tavassoli T, Bellesheim K, Tommerdahl M, Holden JM, Kolevzon A, Buxbaum JD

Abstract
Although tactile reactivity issues are commonly reported in children with autism spectrum disorder (ASD), the underlying mechanisms are poorly understood. Less feed-forward inhibition has been proposed as a potential mechanism for some symptoms of ASD. We tested static and dynamic tactile thresholds as a behavioral proxy of feed-forward inhibition in 42 children (21 children with ASD and 21 typically developing [TD] children). Subthreshold conditioning typically raises the dynamic detection threshold, thus comparison of the dynamic to the static threshold generates a metric that predicts gamma-aminobutyric acid (GABA) mediated feed-forward inhibition. Children with ASD had marginally higher static thresholds and a significantly lower ratio between thresholds as compared with TD children. The lower ratio, only seen in children with ASD, might be indicative of less inhibition. Static thresholds were correlated with autism spectrum quotient scores, indicating the higher the tactile threshold, the more ASD traits. The amount of feed-forward inhibition (ratio between dynamic/static) was negatively correlated with autism diagnostic observation schedule repetitive behavior scores, meaning the less inhibition the more ASD symptoms. In summary, children with ASD showed altered tactile processing compared with TD children; thus measuring static and dynamic thresholds could be a potential biomarker for ASD and might be useful for prediction of treatment response with therapeutics, including those that target the GABAergic system. Autism Res 2015. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

PMID: 26568449 [PubMed - as supplied by publisher]

Acute behavioral crises in psychiatric inpatients with autism spectrum disorder (ASD): recognition of concomitant medical or non-ASD psychiatric conditions predicts enhanced improvement.

November 17, 2015 - 9:44am
Related Articles

Acute behavioral crises in psychiatric inpatients with autism spectrum disorder (ASD): recognition of concomitant medical or non-ASD psychiatric conditions predicts enhanced improvement.

Res Dev Disabil. 2015 Mar;38:242-55

Authors: Guinchat V, Cravero C, Diaz L, Périsse D, Xavier J, Amiet C, Gourfinkel-An I, Bodeau N, Wachtel L, Cohen D, Consoli A

Abstract
During adolescence, some individuals with autism spectrum disorder (ASD) engage in severe challenging behaviors, such as aggression, self-injury, disruption, agitation and tantrums. We aimed to assess risk factors associated with very acute behavioral crises in adolescents with ASD admitted to a dedicated neurobehavioral unit. We included retrospectively in 2008 and 2009 29 adolescents and young adults with ASD hospitalized for severe challenging behaviors and proposed a guideline (Perisse et al., 2010) that we applied prospectively for 29 patients recruited for the same indications between 2010 and 2012. In total, 58 patients were admitted (n=70 hospitalizations, mean age=15.66 (±4.07) years, 76% male). We systematically collected data describing socio-demographic characteristics, clinical variables (severity, presence of language, cognitive level), comorbid organic conditions, etiologic diagnosis of the episode, and treatments. We explored predictors of Global Assessment Functioning Scale (GAFS) score and duration of hospitalization at discharge. All but 2 patients exhibited severe autistic symptoms and intellectual disability (ID), and two-thirds had no functional verbal language. During the inpatient stay (mean=84.3 (±94.9) days), patients doubled on average their GAFS scores (mean=17.66 (±9.05) at admission vs. mean=31.4 (±9.48) at discharge). Most common etiologies for acute behavioral crises were organic causes [n=20 (28%), including epilepsy: n=10 (14%) and painful medical conditions: n=10 (14%)], environmental causes [n=17 (25%) including lack of treatment: n=11 (16%) and adjustment disorder: n=6 (9%)], and non-ASD psychiatric condition [n=33 (48%) including catatonia: n=5 (7%), major depressive episode: n=6 (9%), bipolar disorder: n=4 (6%), schizophrenia: n=6 (9%), other/unknown diagnosis: n=12 (17%)]. We found no influence of age, gender, socio-economic status, migration, level of ID, or history of seizure on improvement of GAFS score at discharge. Severity of autism at admission was the only negative predictor (p<.001). Painful medical conditions (p=.04), non-ASD psychiatric diagnoses (p=.001), prior usage of specialized ASD care programs (p=.004), functional language (p=.007), as well as a higher number of challenging behaviors upon admission (p=.001) were associated with higher GAFS scores at discharge. Clinical severity at admission, based on the number of challenging behaviors (r=.35, p=.003) and GAFS score (r=-.32, p=.008) was correlated with a longer inpatient stay. Longer hospitalization was however correlated (r=.27, p=.03) with higher GAFS score at discharge even after adjustment for confounding factors. Challenging behaviors among adolescents with ASD may stem from diverse risk factors, including environmental problems, comorbid acute psychiatric conditions, or somatic illness such as epilepsy or acute pain. The management of these behavioral challenges requires a unified, multidisciplinary approach.

PMID: 25575287 [PubMed - indexed for MEDLINE]

'Neonatal' Nav1.2 reduces neuronal excitability and affects seizure susceptibility and behaviour.

November 17, 2015 - 9:44am
Related Articles

'Neonatal' Nav1.2 reduces neuronal excitability and affects seizure susceptibility and behaviour.

Hum Mol Genet. 2015 Mar 1;24(5):1457-68

Authors: Gazina EV, Leaw BT, Richards KL, Wimmer VC, Kim TH, Aumann TD, Featherby TJ, Churilov L, Hammond VE, Reid CA, Petrou S

Abstract
Developmentally regulated alternative splicing produces 'neonatal' and 'adult' isoforms of four Na(+) channels in human brain, NaV1.1, NaV1.2, NaV1.3 and NaV1.6. Heterologously expressed 'neonatal' NaV1.2 channels are less excitable than 'adult' channels; however, functional importance of this difference is unknown. We hypothesized that the 'neonatal' NaV1.2 may reduce neuronal excitability and have a seizure-protective role during early brain development. To test this hypothesis, we generated NaV1.2(adult) mice expressing only the 'adult' NaV1.2, and compared the firing properties of pyramidal cortical neurons, as well as seizure susceptibility, between the NaV1.2(adult) and wild-type (WT) mice at postnatal day 3 (P3), when the 'neonatal' isoform represents 65% of the WT NaV1.2. We show significant increases in action potential firing in NaV1.2(adult) neurons and in seizure susceptibility of NaV1.2(adult) mice, supporting our hypothesis. At postnatal day 15 (P15), when 17% of the WT NaV1.2 is 'neonatal', the firing properties of NaV1.2(adult) and WT neurons converged. However, inhibitory postsynaptic currents in NaV1.2(adult) neurons were larger and the expression level of Scn2a mRNA was 24% lower compared with the WT. The enhanced seizure susceptibility of the NaV1.2(adult) mice persisted into adult age. The adult NaV1.2(adult) mice also exhibited greater risk-taking behaviour. Overall, our data reveal a significant impact of 'neonatal' NaV1.2 on neuronal excitability, seizure susceptibility and behaviour and may contribute to our understanding of NaV1.2 roles in health and diseases such as epilepsy and autism.

PMID: 25378553 [PubMed - indexed for MEDLINE]

IL1RAPL1 knockout mice show spine density decrease, learning deficiency, hyperactivity and reduced anxiety-like behaviours.

November 17, 2015 - 9:44am
Related Articles

IL1RAPL1 knockout mice show spine density decrease, learning deficiency, hyperactivity and reduced anxiety-like behaviours.

Sci Rep. 2014;4:6613

Authors: Yasumura M, Yoshida T, Yamazaki M, Abe M, Natsume R, Kanno K, Uemura T, Takao K, Sakimura K, Kikusui T, Miyakawa T, Mishina M

Abstract
IL-1 receptor accessory protein-like 1 (IL1RAPL1) is responsible for nonsyndromic intellectual disability and is associated with autism. IL1RAPL1 mediates excitatory synapse formation through trans-synaptic interaction with PTPδ. Here, we showed that the spine density of cortical neurons was significantly reduced in IL1RAPL1 knockout mice. The spatial reference and working memories and remote fear memory were mildly impaired in IL1RAPL1 knockout mice. Furthermore, the behavioural flexibility was slightly reduced in the T-maze test. Interestingly, the performance of IL1RAPL1 knockout mice in the rotarod test was significantly better than that of wild-type mice. Moreover, IL1RAPL1 knockout mice consistently exhibited high locomotor activity in all the tasks examined. In addition, open-space and height anxiety-like behaviours were decreased in IL1RAPL1 knockout mice. These results suggest that IL1RAPL1 ablation resulted in spine density decrease and affected not only learning but also behavioural flexibility, locomotor activity and anxiety.

PMID: 25312502 [PubMed - indexed for MEDLINE]

Chromosome 17q21.31 duplication syndrome: Description of a new familiar case and further delineation of the clinical spectrum.

November 14, 2015 - 6:39am

Chromosome 17q21.31 duplication syndrome: Description of a new familiar case and further delineation of the clinical spectrum.

Eur J Paediatr Neurol. 2015 Oct 22;

Authors: Natacci F, Alfei E, Tararà L, D'Arrigo S, Zuffardi O, Gentilin B, Pantaleoni C

Abstract
INTRODUCTION: 17q21.31 microduplication syndrome is a recently described condition associated with a broad clinical spectrum, of which psychomotor delay, behavioral disorders and poor social interaction seem to be the most consistent features. Only seven patients have been reported thus far. All have behavioral disorders reminiscent of the autistic spectrum with intellectual skills ranging from normal to mild intellectual deficiency. Other features are variable with no striking common phenotypic features.
CASE STUDY: Here we describe the segregation of 17q21.31 duplication in an Italian family.
DISCUSSION: Clinical features and genetic data are reported, and compared with previously reported patients with 17q21.31 microduplication. A comparison of clinical manifestations between deletion and duplication syndromes of the chromosome regione is provided.

PMID: 26565673 [PubMed - as supplied by publisher]

PTEN hamartoma tumor syndrome.

November 14, 2015 - 6:39am

PTEN hamartoma tumor syndrome.

Handb Clin Neurol. 2015;132:129-37

Authors: Mester J, Charis E

Abstract
PTEN hamartoma tumor syndrome (PHTS) is the molecular diagnostic term describing patients with Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, and other clinical presentations with germline mutation of the PTEN tumor suppressor gene. PHTS confers increased risks for specific malignancies, most notably breast, thyroid, renal, and endometrial cancers. Benign tumors are common, affecting a variety of tissues, and can range from subtle skin papules requiring no treatment to devastating vascular anomalies. There is also a broad range of neurodevelopmental effects, with some patients having no challenges and others with severe autism spectrum disorder and mental retardation. While most cases are inherited in a family for generations, following an autosomal dominant pattern, at least 10% and perhaps as many as 44% of cases are due to a new (de novo) mutation. Clinical presentations can vary dramatically from patient to patient, even among those in the same family. Features of this condition that may assist in diagnosis prior to cancer development can be subtle and difficult to recognize. This chapter will help the reader identify which patients should be referred for genetics evaluation and how to manage patients diagnosed with this rare condition.

PMID: 26564076 [PubMed - in process]

Two rare deletions upstream of the NRXN1 gene (2p16.3) affecting the non-coding mRNA AK127244 segregate with diverse psychopathological phenotypes in a family.

November 14, 2015 - 6:39am

Two rare deletions upstream of the NRXN1 gene (2p16.3) affecting the non-coding mRNA AK127244 segregate with diverse psychopathological phenotypes in a family.

Eur J Med Genet. 2015 Nov 9;

Authors: Duong LT, Hoeffding LK, Petersen KB, Knudsen CD, Thygesen JH, Klitten LL, Tommerup N, Ingason A, Werge T

Abstract
CNVs spanning the 2p16.3 (NRXN1) and the 15q11.2 gene rich region have been associated with severe neuropsychiatric disorders including schizophrenia. Recently, studies have also revealed that CNVs in non-coding regions play an essential role in genomic variability in addition to disease susceptibility. In this study, we describe a family affected by a wide range of psychiatric disorders including early onset schizophrenia, schizophreniform disorder, and affective disorders. Microarray analysis identified two rare deletions immediately upstream of the NRXN1 gene affecting the non-coding mRNA AK127244 in addition to the pathogenic 15q11.2 deletion in distinct family members. The two deletions upstream of the NRXN1 gene were found to segregate with psychiatric disorders in the family and further similar deletions have been observed in patients diagnosed with autism spectrum disorder. Thus, we suggest that non-coding regions upstream of the NRXN1 gene affecting AK127244 might (as NRXN1) contain susceptibility regions for a wide spectrum of neuropsychiatric disorders.

PMID: 26563496 [PubMed - as supplied by publisher]

Autism: Pathophysiology and promising herbal remedies.

November 13, 2015 - 6:35am

Autism: Pathophysiology and promising herbal remedies.

Curr Pharm Des. 2015 Nov 12;

Authors: Bahmani M, Sarrafchi A, Shirzad H, Rafieian-Kopaei M

Abstract
Autism is a comprehensive growth abnormality in which social skills, language, communication, and behavioral skills are developed with delay and as diversionary. The reasons for autism are unclear, but various theories of genetics, immunity, biological, and psychosocial factors have been proffered. In fact, autism is a complex disorder with distinct causes that usually co-occur. Although no medicine has been recognized to treat this disorder, pharmacological treatments can be effective in reducing its signs, such as self-mutilation, aggression, repetitive and stereotyped behaviors, inattention, hyperactivity, and sleeping disorders. Recently, complementary and alternative approaches have been considered to treat autism. Ginkgo biloba is one of the most effective plants with an old history of applications in neuropsychological disorders which recently is used for autism. The present review discusses the recent findings, pathophysiology, and etiology of autism and thereafter addresses the promising results of herbal remedies.

PMID: 26561063 [PubMed - as supplied by publisher]

Convergence of Hippocampal Pathophysiology in Syngap+/- and Fmr1-/y Mice.

November 13, 2015 - 6:35am

Convergence of Hippocampal Pathophysiology in Syngap+/- and Fmr1-/y Mice.

J Neurosci. 2015 Nov 11;35(45):15073-81

Authors: Barnes SA, Wijetunge LS, Jackson AD, Katsanevaki D, Osterweil EK, Komiyama NH, Grant SG, Bear MF, Nägerl UV, Kind PC, Wyllie DJ

Abstract
UNLABELLED: Previous studies have hypothesized that diverse genetic causes of intellectual disability (ID) and autism spectrum disorders (ASDs) converge on common cellular pathways. Testing this hypothesis requires detailed phenotypic analyses of animal models with genetic mutations that accurately reflect those seen in the human condition (i.e., have structural validity) and which produce phenotypes that mirror ID/ASDs (i.e., have face validity). We show that SynGAP haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and occludes the synaptic pathophysiology associated with deletion of the Fmr1 gene. Syngap(+/-) and Fmr1(-/y) mice show increases in basal protein synthesis and metabotropic glutamate receptor (mGluR)-dependent long-term depression that, unlike in their wild-type controls, is independent of new protein synthesis. Basal levels of phosphorylated ERK1/2 are also elevated in Syngap(+/-) hippocampal slices. Super-resolution microscopy reveals that Syngap(+/-) and Fmr1(-/y) mice show nanoscale alterations in dendritic spine morphology that predict an increase in biochemical compartmentalization. Finally, increased basal protein synthesis is rescued by negative regulators of the mGlu subtype 5 receptor and the Ras-ERK1/2 pathway, indicating that therapeutic interventions for fragile X syndrome may benefit patients with SYNGAP1 haploinsufficiency.
SIGNIFICANCE STATEMENT: As the genetics of intellectual disability (ID) and autism spectrum disorders (ASDs) are unraveled, a key issue is whether genetically divergent forms of these disorders converge on common biochemical/cellular pathways and hence may be amenable to common therapeutic interventions. This study compares the pathophysiology associated with the loss of fragile X mental retardation protein (FMRP) and haploinsufficiency of synaptic GTPase-activating protein (SynGAP), two prevalent monogenic forms of ID. We show that Syngap(+/-) mice phenocopy Fmr1(-/y) mice in the alterations in mGluR-dependent long-term depression, basal protein synthesis, and dendritic spine morphology. Deficits in basal protein synthesis can be rescued by pharmacological interventions that reduce the mGlu5 receptor-ERK1/2 signaling pathway, which also rescues the same deficit in Fmr1(-/y) mice. Our findings support the hypothesis that phenotypes associated with genetically diverse forms of ID/ASDs result from alterations in common cellular/biochemical pathways.

PMID: 26558778 [PubMed - in process]

Deep phenotyping: The details of disease.

November 13, 2015 - 6:35am
Related Articles

Deep phenotyping: The details of disease.

Nature. 2015 Nov 5;527(7576):S14-5

Authors: Delude CM

PMID: 26536218 [PubMed - indexed for MEDLINE]

Evidence linking FMR1 mRNA and attentional demands of stepping and postural control in women with the premutation.

November 13, 2015 - 6:35am
Related Articles

Evidence linking FMR1 mRNA and attentional demands of stepping and postural control in women with the premutation.

Neurobiol Aging. 2015 Mar;36(3):1400-8

Authors: Hocking DR, Kraan CM, Godler DE, Bui QM, Li X, Bradshaw JL, Georgiou-Karistianis N, Metcalfe SA, Archibald AD, Turbitt E, Fielding J, Trollor J, Cohen J, Cornish KM

Abstract
Recent studies in young adult females with the fragile X mental retardation 1 (FMR1) gene premutation (PM) have shown subtle but significant impairments in executive control and postural stability. Less is known about the influence of age and FMR1 gene expression on executive control and postural stability in females with the PM. Here, we examined the attentional demands of reactive stepping using a well-validated measure of choice stepping reaction time under dual-task interference. We explored the interrelationships between step initiation times during a concurrent verbal fluency task and specific impairments in executive control previously reported in females with the PM. Our results showed increased dual-task interference on step initiation times and variability in female PM compared with control subjects. In addition, we observed greater choice stepping reaction time dual-task costs above the breakpoint of 81 CGG repeats relative to below this CGG range. Dual-task interference on both reaction time and movement time were significantly predicted by low working memory capacity in female PM carriers. Importantly, we revealed that FMR1 messenger RNA level is the most significant predictor accounting for dual-task stepping variability in both reaction time and movement time in PM females. These findings for the first time provide evidence linking elevated FMR1 messenger RNA levels that have been previously associated with FMR1 RNA toxicity and deficits in cerebellar motor and cognitive networks in a subgroup of at-risk PM women.

PMID: 25541421 [PubMed - indexed for MEDLINE]

Visual sensorial impairments in neurodevelopmental disorders: evidence for a retinal phenotype in Fragile X Syndrome.

November 13, 2015 - 6:35am
Related Articles

Visual sensorial impairments in neurodevelopmental disorders: evidence for a retinal phenotype in Fragile X Syndrome.

PLoS One. 2014;9(8):e105996

Authors: Rossignol R, Ranchon-Cole I, Pâris A, Herzine A, Perche A, Laurenceau D, Bertrand P, Cercy C, Pichon J, Mortaud S, Briault S, Menuet A, Perche O

Abstract
Visual sensory impairments are common in Mental Deficiency (MD) and Autism Spectrum Disorder (ASD). These defects are linked to cerebral dysfunction in the visual cortical area characterized by the deregulation of axon growth/guidance and dendrite spine immaturity of neurons. However, visual perception had not been addressed, although the retina is part of the central nervous system with a common embryonic origin. Therefore, we investigated retinal perception, the first event of vision, in a murine model of MD with autistic features. We document that retinal function is altered in Fmr1 KO mice, a model of human Fragile X Syndrome. Indeed, In Fmr1 KO mice had a lower retinal function characterized by a decreased photoreceptors neuron response, due to a 40% decrease in Rhodopsin content and to Rod Outer Segment destabilization. In addition, we observed an alteration of the visual signal transmission between photoreceptors and the inner retina which could be attributed to deregulations of pre- and post- synaptic proteins resulting in retinal neurons synaptic destabilization and to retinal neurons immaturity. Thus, for the first time, we demonstrated that retinal perception is altered in a murine model of MD with autistic features and that there are strong similarities between cerebral and retinal cellular and molecular defects. Our results suggest that both visual perception and integration must be taken into account in assessing visual sensory impairments in MD and ASD.

PMID: 25153086 [PubMed - indexed for MEDLINE]

The autism inpatient collection: methods and preliminary sample description.

November 12, 2015 - 6:26am

The autism inpatient collection: methods and preliminary sample description.

Mol Autism. 2015;6:61

Authors: Siegel M, Smith KA, Mazefsky C, Gabriels RL, Erickson C, Kaplan D, Morrow EM, Wink L, Santangelo SL, Autism and Developmental Disorders Inpatient Research Collaborative (ADDIRC)

Abstract
BACKGROUND: Individuals severely affected by autism spectrum disorder (ASD), including those with intellectual disability, expressive language impairment, and/or self-injurious behavior (SIB), are underrepresented in the ASD literature and extant collections of phenotypic and biological data. An understanding of ASD's etiology and subtypes can only be as complete as the studied samples are representative.
METHODS: The Autism Inpatient Collection (AIC) is a multi-site study enrolling children and adolescents with ASD aged 4-20 years admitted to six specialized inpatient psychiatry units. Enrollment began March, 2014, and continues at a rate of over 400 children annually. Measures characterizing adaptive and cognitive functioning, communication, externalizing behaviors, emotion regulation, psychiatric co-morbidity, self-injurious behavior, parent stress, and parent self-efficacy are collected. ASD diagnosis is confirmed by the Autism Diagnostic Observation Schedule - 2 (ADOS-2) and extensive inpatient observation. Biological samples from probands and their biological parents are banked and processed for DNA extraction and creation of lymphoblastoid cell lines.
RESULTS: Sixty-one percent of eligible subjects were enrolled. The first 147 subjects were an average of 12.6 years old (SD 3.42, range 4-20); 26.5 % female; 74.8 % Caucasian, and 81.6 % non-Hispanic/non-Latino. Mean non-verbal intelligence quotient IQ = 70.9 (SD 29.16, range 30-137) and mean adaptive behavior composite score = 55.6 (SD 12.9, range 27-96). A majority of subjects (52.4 %) were non- or minimally verbal. The average Aberrant Behavior Checklist - Irritability Subscale score was 28.6, well above the typical threshold for clinically concerning externalizing behaviors, and 26.5 % of the sample engaged in SIB. Females had more frequent and severe SIB than males.
CONCLUSIONS: Preliminary data indicate that the AIC has a rich representation of the portion of the autism spectrum that is understudied and underrepresented in extant data collections. More than half of the sample is non- or minimally verbal, over 40 % have intellectual disability, and over one quarter exhibit SIB. The AIC is a substantial new resource for study of the full autism spectrum, which will augment existing data on higher-functioning cohorts and facilitate the identification of genetic subtypes and novel treatment targets. The AIC investigators welcome collaborations with other investigators, and access to the AIC phenotypic data and biosamples may be requested through the Simons Foundation (www.sfari.org).

PMID: 26557975 [PubMed]

Mutation screening of SCN2A in schizophrenia and identification of a novel loss-of-function mutation.

November 12, 2015 - 6:26am

Mutation screening of SCN2A in schizophrenia and identification of a novel loss-of-function mutation.

Psychiatr Genet. 2015 Nov 9;

Authors: Carroll LS, Woolf R, Ibrahim Y, Williams HJ, Dwyer S, Walters J, Kirov G, O'Donovan MC, Owen MJ

Abstract
OBJECTIVES: There is a growing body of evidence suggesting a shared genetic susceptibility between many neuropsychiatric disorders, including schizophrenia, autism, intellectual disability (ID) and epilepsy. The sodium channel, voltage-gated type II α subunit gene SCN2A has been shown to exhibit loss-of-function (LoF) mutations in individuals with seizure disorders, ID, autism and schizophrenia. The role of LoF mutations in schizophrenia is still uncertain with only one such mutation identified to date.
METHODS: To seek additional evidence for a role for LoF mutations at SCN2A in schizophrenia we performed mutation screening of the entire coding sequence in 980 schizophrenia cases. Given an absence of LoF mutations in a public exome cohort (ESP6500, N=6503), we did not additionally sequence controls.
RESULTS: We identified a novel, nonsense (i.e. stop codon) mutation in one case (E169X) that is absent in 4300 European-American and 2203 African-American individuals from the NHLBI Exome Sequencing Project. This is the second LoF allele identified in a schizophrenia case to date. We also show a novel, missense variant, V1282F, that occurs in two cases and is absent in the control dataset.
CONCLUSION: We argue that very rare, LoF mutations at SCN2A act in a moderately penetrant manner to increase the risk of developing several neuropsychiatric disorders including seizure disorders, ID, autism and schizophrenia.

PMID: 26555645 [PubMed - as supplied by publisher]

A 3' untranslated region variant in FMR1 eliminates neuronal activity-dependent translation of FMRP by disrupting binding of the RNA-binding protein HuR.

November 11, 2015 - 6:23am

A 3' untranslated region variant in FMR1 eliminates neuronal activity-dependent translation of FMRP by disrupting binding of the RNA-binding protein HuR.

Proc Natl Acad Sci U S A. 2015 Nov 9;

Authors: Suhl JA, Muddashetty RS, Anderson BR, Ifrim MF, Visootsak J, Bassell GJ, Warren ST

Abstract
Fragile X syndrome is a common cause of intellectual disability and autism spectrum disorder. The gene underlying the disorder, fragile X mental retardation 1 (FMR1), is silenced in most cases by a CGG-repeat expansion mutation in the 5' untranslated region (UTR). Recently, we identified a variant located in the 3'UTR of FMR1 enriched among developmentally delayed males with normal repeat lengths. A patient-derived cell line revealed reduced levels of endogenous fragile X mental retardation protein (FMRP), and a reporter containing a patient 3'UTR caused a decrease in expression. A control reporter expressed in cultured mouse cortical neurons showed an expected increase following synaptic stimulation that was absent when expressing the patient reporter, suggesting an impaired response to neuronal activity. Mobility-shift assays using a control RNA detected an RNA-protein interaction that is lost with the patient RNA, and HuR was subsequently identified as an associated protein. Cross-linking immunoprecipitation experiments identified the locus as an in vivo target of HuR, supporting our in vitro findings. These data suggest that the disrupted interaction of HuR impairs activity-dependent translation of FMRP, which may hinder synaptic plasticity in a clinically significant fashion.

PMID: 26554012 [PubMed - as supplied by publisher]

Merging data from genetic and epigenetic approaches to better understand autistic spectrum disorder.

November 10, 2015 - 6:20am

Merging data from genetic and epigenetic approaches to better understand autistic spectrum disorder.

Epigenomics. 2015 Nov 9;

Authors: Grayson DR, Guidotti A

Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that is characterized by a wide range of cognitive and behavioral abnormalities. Genetic research has identified large numbers of genes that contribute to ASD phenotypes. There is compelling evidence that environmental factors contribute to ASD through influences that differentially impact the brain through epigenetic mechanisms. Both genetic mutations and epigenetic influences alter gene expression in different cell types of the brain. Mutations impact the expression of large numbers of genes and also have downstream consequences depending on specific pathways associated with the mutation. Environmental factors impact the expression of sets of genes by altering methylation/hydroxymethylation patterns, local histone modification patterns and chromatin remodeling. Herein, we discuss recent developments in the research of ASD with a focus on epigenetic pathways as a complement to current genetic screening.

PMID: 26551091 [PubMed - as supplied by publisher]

Neuroimaging endophenotypes in autism spectrum disorder.

November 10, 2015 - 6:20am
Related Articles

Neuroimaging endophenotypes in autism spectrum disorder.

CNS Spectr. 2015 Aug;20(4):412-26

Authors: Mahajan R, Mostofsky SH

Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder that has a strong genetic basis, and is heterogeneous in its etiopathogenesis and clinical presentation. Neuroimaging studies, in concert with neuropathological and clinical research, have been instrumental in delineating trajectories of development in children with ASD. Structural neuroimaging has revealed ASD to be a disorder with general and regional brain enlargement, especially in the frontotemporal cortices, while functional neuroimaging studies have highlighted diminished connectivity, especially between frontal-posterior regions. The diverse and specific neuroimaging findings may represent potential neuroendophenotypes, and may offer opportunities to further understand the etiopathogenesis of ASD, predict treatment response, and lead to the development of new therapies.

PMID: 26234701 [PubMed - indexed for MEDLINE]

High Gestational Folic Acid Supplementation Alters Expression of Imprinted and Candidate Autism Susceptibility Genes in a sex-Specific Manner in Mouse Offspring.

November 9, 2015 - 6:19am

High Gestational Folic Acid Supplementation Alters Expression of Imprinted and Candidate Autism Susceptibility Genes in a sex-Specific Manner in Mouse Offspring.

J Mol Neurosci. 2015 Nov 7;

Authors: Barua S, Kuizon S, Ted Brown W, Junaid MA

Abstract
Maternal nutrients play critical roles in modulating epigenetic events and exert long-term influences on the progeny's health. Folic acid (FA) supplementation during pregnancy has decreased the incidence of neural tube defects in newborns, but the influence of high doses of maternal FA supplementation on infants' brain development is unclear. The present study was aimed at investigating the effects of a high dose of gestational FA on the expression of genes in the cerebral hemispheres (CHs) of 1-day-old pups. One week prior to mating and throughout the entire period of gestation, female C57BL/6J mice were fed a diet, containing FA at either 2 mg/kg (control diet (CD)) or 20 mg/kg (high maternal folic acid (HMFA)). At postnatal day 1, pups from different dams were sacrificed and CH tissues were collected. Quantitative RT-PCR and Western blot analysis confirmed sex-specific alterations in the expression of several genes that modulate various cellular functions (P < 0.05) in pups from the HMFA group. Genomic DNA methylation analysis showed no difference in the level of overall methylation in pups from the HMFA group. These findings demonstrate that HMFA supplementation alters offsprings' CH gene expression in a sex-specific manner. These changes may influence infants' brain development.

PMID: 26547318 [PubMed - as supplied by publisher]

Inhibition of Group I Metabotropic Glutamate Receptors Reverses Autistic-Like Phenotypes Caused by Deficiency of the Translation Repressor eIF4E Binding Protein 2.

November 6, 2015 - 6:15am
Related Articles

Inhibition of Group I Metabotropic Glutamate Receptors Reverses Autistic-Like Phenotypes Caused by Deficiency of the Translation Repressor eIF4E Binding Protein 2.

J Neurosci. 2015 Aug 5;35(31):11125-32

Authors: Aguilar-Valles A, Matta-Camacho E, Khoutorsky A, Gkogkas C, Nader K, Lacaille JC, Sonenberg N

Abstract
UNLABELLED: Exacerbated mRNA translation during brain development has been linked to autism spectrum disorders (ASDs). Deletion of the eukaryotic initiation factor 4E (eIF4E)-binding protein 2 gene (Eif4ebp2), encoding the suppressor of mRNA translation initiation 4E-BP2, leads to an imbalance in excitatory-to-inhibitory neurotransmission and ASD-like behaviors. Inhibition of group I metabotropic glutamate receptors (mGluRs) mGluR1 and mGluR5 reverses the autistic phenotypes in several ASD mouse models. Importantly, these receptors control synaptic physiology via activation of mRNA translation. We investigated the potential reversal of autistic-like phenotypes in Eif4ebp2(-/-) mice by using antagonists of mGluR1 (JNJ16259685) or mGluR5 (fenobam). Augmented hippocampal mGluR-induced long-term depression (LTD; or chemically induced mGluR-LTD) in Eif4ebp2(-/-) mice was rescued by mGluR1 or mGluR5 antagonists. While rescue by mGluR5 inhibition occurs through the blockade of a protein synthesis-dependent component of LTD, normalization by mGluR1 antagonists requires the activation of protein synthesis. Synaptically induced LTD was deficient in Eif4ebp2(-/-) mice, and this deficit was not rescued by group I mGluR antagonists. Furthermore, a single dose of mGluR1 (0.3 mg/kg) or mGluR5 (3 mg/kg) antagonists in vivo reversed the deficits in social interaction and repetitive behaviors (marble burying) in Eif4ebp2(-/-) mice. Our results demonstrate that Eif4ebp2(-/-) mice serve as a relevant model to test potential therapies for ASD symptoms. In addition, we provide substantive evidence that the inhibition of mGluR1/mGluR5 is an effective treatment for physiological and behavioral alterations caused by exacerbated mRNA translation initiation.
SIGNIFICANCE STATEMENT: Exacerbated mRNA translation during brain development is associated with several autism spectrum disorders (ASDs). We recently demonstrated that the deletion of a negative regulator of mRNA translation initiation, the eukaryotic initiation factor 4E-binding protein 2, leads to ASD-like behaviors and increased excitatory synaptic activity. Here we demonstrated that autistic behavioral and electrophysiological phenotypes can be treated in adult mice with antagonists of group I metabotropic glutamate receptors (mGluRs), which have been previously used in other ASD models (i.e., fragile X syndrome). These findings support the use of group I mGluR antagonists as a potential therapy that extends to autism models involving exacerbated mRNA translation initiation.

PMID: 26245973 [PubMed - indexed for MEDLINE]

Expansion of the clinical phenotype associated with mutations in activity-dependent neuroprotective protein.

November 6, 2015 - 6:15am
Related Articles

Expansion of the clinical phenotype associated with mutations in activity-dependent neuroprotective protein.

J Med Genet. 2014 Sep;51(9):587-9

Authors: Pescosolido MF, Schwede M, Johnson Harrison A, Schmidt M, Gamsiz ED, Chen WS, Donahue JP, Shur N, Jerskey BA, Phornphutkul C, Morrow EM

PMID: 25057125 [PubMed - indexed for MEDLINE]

Pages