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How might epigenetic dysregulation in early embryonic life contribute to autism spectrum disorder?

February 18, 2015 - 6:14am

How might epigenetic dysregulation in early embryonic life contribute to autism spectrum disorder?

Epigenomics. 2015 Feb;7(1):1-4

Authors: Berko ER, Greally JM

PMID: 25687459 [PubMed - in process]

Genetic and Developmental Perspective of Language Abnormality in Autism and Schizophrenia: One Disease Occurring at Different Ages in Humans?

February 18, 2015 - 6:14am

Genetic and Developmental Perspective of Language Abnormality in Autism and Schizophrenia: One Disease Occurring at Different Ages in Humans?

Neuroscientist. 2015 Feb 16;

Authors: Wang HG, Jeffries JJ, Wang TF

Abstract
Language and communication through it are two of the defining features of normally developed human beings. However, both these functions are often impaired in autism and schizophrenia. In the former disorder, the problem usually emerges in early childhood (~2 years old) and typically includes a lack of communication. In the latter condition, the language problems usually occur in adolescence and adulthood and presents as disorganized speech. What are the fundamental mechanisms underlying these two disorders? Is there a shared genetic basis? Are the traditional beliefs about them true? Are there any common strategies for their prevention and management? To answer these questions, we searched PubMed by using autism, schizophrenia, gene, and language abnormality as keywords, and we reconsidered the basic concepts about these two diseases or syndromes. We found many functional genes, for example, FOXP2, COMT, GABRB3, and DISC1, are actually implicated in both of them. After observing the symptoms, genetic correlates, and temporal progression of these two disorders as well as their relationships more carefully, we now infer that the occurrence of these two diseases is likely developmentally regulated via interaction between the genome and the environment. Furthermore, we propose a unified view of autism and schizophrenia: a single age-dependently occurred disease that is newly named as Systemic Integral Disorder: if occurring in children before age 2, it is called autism; if in adolescence or a later age, it is called schizophrenia.

PMID: 25686622 [PubMed - as supplied by publisher]

A pilot controlled trial of insulin-like growth factor-1 in children with Phelan-McDermid syndrome.

February 17, 2015 - 8:16am
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A pilot controlled trial of insulin-like growth factor-1 in children with Phelan-McDermid syndrome.

Mol Autism. 2014;5(1):54

Authors: Kolevzon A, Bush L, Wang AT, Halpern D, Frank Y, Grodberg D, Rapaport R, Tavassoli T, Chaplin W, Soorya L, Buxbaum JD

Abstract
BACKGROUND: Autism spectrum disorder (ASD) is now understood to have multiple genetic risk genes and one example is SHANK3. SHANK3 deletions and mutations disrupt synaptic function and result in Phelan-McDermid syndrome (PMS), which causes a monogenic form of ASD with a frequency of at least 0.5% of ASD cases. Recent evidence from preclinical studies with mouse and human neuronal models of SHANK3 deficiency suggest that insulin-like growth factor-1 (IGF-1) can reverse synaptic plasticity and motor learning deficits. The objective of this study was to pilot IGF-1 treatment in children with PMS to evaluate safety, tolerability, and efficacy for core deficits of ASD, including social impairment and restricted and repetitive behaviors.
METHODS: Nine children with PMS aged 5 to 15 were enrolled in a placebo-controlled, double-blind, crossover design study, with 3 months of treatment with IGF-1 and 3 months of placebo in random order, separated by a 4-week wash-out period.
RESULTS: Compared to the placebo phase, the IGF-1 phase was associated with significant improvement in both social impairment and restrictive behaviors, as measured by the Aberrant Behavior Checklist and the Repetitive Behavior Scale, respectively. IGF-1 was found to be well tolerated and there were no serious adverse events in any participants.
CONCLUSIONS: This study establishes the feasibility of IGF-1 treatment in PMS and contributes pilot data from the first controlled treatment trial in the syndrome. Results also provide proof of concept to advance knowledge about developing targeted treatments for additional causes of ASD associated with impaired synaptic development and function.

PMID: 25685306 [PubMed]

The RNA-binding protein Celf6 is highly expressed in diencephalic nuclei and neuromodulatory cell populations of the mouse brain.

February 16, 2015 - 7:17am

The RNA-binding protein Celf6 is highly expressed in diencephalic nuclei and neuromodulatory cell populations of the mouse brain.

Brain Struct Funct. 2015 Feb 15;

Authors: Maloney SE, Khangura E, Dougherty JD

Abstract
The gene CUG-BP, Elav-like factor 6 (CELF6) appears to be important for proper functioning of neurocircuitry responsible for behavioral output. We previously discovered that polymorphisms in or near CELF6 may be associated with autism spectrum disorder (ASD) in humans and that the deletion of this gene in mice results in a partial ASD-like phenotype. Here, to begin to understand which circuits might mediate these behavioral disruptions, we sought to establish in what structures, with what abundance, and at which ages Celf6 protein is present in the mouse brain. Using both a knockout-validated antibody to Celf6 and a novel transgenic mouse line, we characterized Celf6 expression in the mouse brain across development. Celf6 gene products were present early in neurodevelopment and in adulthood. The greatest protein expression was observed in distinct nuclei of the diencephalon and neuromodulatory cell populations of the midbrain and hindbrain, with clear expression in dopaminergic, noradrenergic, histaminergic, serotonergic and cholinergic populations, and a variety of presumptive peptidergic cells of the hypothalamus. These results suggest that disruption of Celf6 expression in hypothalamic nuclei may impact a variety of behaviors downstream of neuropeptide activity, while disruption in neuromodulatory transmitter expressing areas such as the ventral tegmental area, substantia nigra, raphe nuclei and locus coeruleus may have far-reaching influences on overall brain activity.

PMID: 25682262 [PubMed - as supplied by publisher]

Annual Research Review: The (epi)genetics of neurodevelopmental disorders in the era of whole-genome sequencing - unveiling the dark matter.

February 14, 2015 - 8:52am

Annual Research Review: The (epi)genetics of neurodevelopmental disorders in the era of whole-genome sequencing - unveiling the dark matter.

J Child Psychol Psychiatry. 2015 Feb 11;

Authors: Kiser DP, Rivero O, Lesch KP

Abstract
BACKGROUND AND SCOPE: Neurodevelopmental disorders (NDDs) are defined by a wide variety of behavioural phenotypes, psychopathology and clinically informed categorical classifications. Diagnostic entities include intellectual disability (ID), the autism spectrum (ASD) and attention-deficit/hyperactivity disorder (ADHD). The aetiopathogenesis of these conditions and disorders involves an interaction between both genetic and environmental risk factors on the developmental trajectory. Despite their remarkable genetic heterogeneity and complexity of pathophysiological mechanisms, NDDs display an overlap in their phenotypic features, a considerable degree of comorbidity as well as sharing of genetic and environmental risk factors. This review aims to provide an overview of the genetics and epigenetic of NDDs.
FINDINGS: Recent evidence suggests a critical role of defined and tightly regulated neurodevelopmental programs running out of control in NDDs, most notably neuronal proliferation and migration, synapse formation and remodelling, as well as neural network configuration resulting in compromised systems connectivity and function. Moreover, the machinery of epigenetic programming, interacting with genetic liability, impacts many of those processes and pathways, thus modifying vulnerability of, and resilience to, NDDs. Consequently, the categorically defined entities of ID, ADHD and ASD are increasingly viewed as disorders on a multidimensional continuum of molecular and cellular deficiencies in neurodevelopment. As such, this range of NDDs displays a broad phenotypic diversity, which may be explained by a combination and interplay of underlying loss- and potential gain-of-function traits.
CONCLUSION: In this overview, we discuss a backbone continuum concept of NDDs by summarizing pertinent findings in genetics and epigenetics. We also provide an appraisal of the genetic overlap versus differences, with a focus on genome-wide screening approaches for (epi)genetic variation. Finally, we conclude with insights from evolutionary psychobiology suggesting positive selection for discrete NDD-associated traits.

PMID: 25677560 [PubMed - as supplied by publisher]

A case with a ring chromosome 13 in a cohort of 203 children with non-syndromic autism and review of the cytogenetic literature.

February 14, 2015 - 8:52am
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A case with a ring chromosome 13 in a cohort of 203 children with non-syndromic autism and review of the cytogenetic literature.

Cytogenet Genome Res. 2014;144(1):1-8

Authors: Charalsawadi C, Maisrikhaw W, Praphanphoj V, Wirojanan J, Hansakunachai T, Roongpraiwan R, Sombuntham T, Ruangdaraganon N, Limprasert P

Abstract
Autistic spectrum disorder (ASD) is a group of neurodevelopmental disorders characterized by impairments of social interaction, communication and restricted, repetitive and stereotyped patterns of behavior, interests and activities. Frequencies of chromosomal abnormalities in cohorts of individuals with ASD varying between 1.2 and 28.6% have been reported. In this study, we evaluated 203 Thai children who met the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), for autistic disorder or pervasive developmental disorder not otherwise specified (PDD-NOS), and who had neither major dysmorphic features nor CGG repeat expansions of the FMR1 gene. A routine G-banding chromosome analysis was performed at a minimum of ISCN 400-550 bands. A chromosomal abnormality was observed in one child (0.5%), a 41-month-old boy with a ring chromosome 13 detected by G-banding analysis and subsequently confirmed by FISH. SNP microarray analysis detected a 2.11-Mb deletion of chromosome 13q34, encompassing 23 genes. The MCF2L and UPF3A genes are among those genes that may explain the autistic features in our case. To the best of our knowledge, only one autistic case with a ring chromosome 13 has been previously reported. In this article, we also systemically reviewed 21 studies that utilized a conventional cytogenetic method to detect chromosomal abnormalities in patients with ASD. When we summed all cases with chromosomal abnormalities, including the case from our study, the frequency of chromosomal abnormalities detected by conventional cytogenetics in patients with ASD was 3.2% (118/3,712).

PMID: 25171325 [PubMed - indexed for MEDLINE]

Variations analysis of NLGN3 and NLGN4X gene in Chinese autism patients.

February 14, 2015 - 8:52am
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Variations analysis of NLGN3 and NLGN4X gene in Chinese autism patients.

Mol Biol Rep. 2014 Jun;41(6):4133-40

Authors: Xu X, Xiong Z, Zhang L, Liu Y, Lu L, Peng Y, Guo H, Zhao J, Xia K, Hu Z

Abstract
Autism is a neurodevelopmental disorder clinically characterized by impairment of social interaction, deficits in verbal communication, as well as stereotypic and repetitive behaviors. Several studies have implicated that abnormal synaptogenesis was involved in the incidence of autism. Neuroligins are postsynaptic cell adhesion molecules and interacted with neurexins to regulate the fine balance between excitation and inhibition of synapses. Recently, mutation analysis, cellular and mice models hinted neuroligin mutations probably affected synapse maturation and function. In this study, four missense variations [p.G426S (NLGN3), p.G84R (NLGN4X), p.Q162 K (NLGN4X) and p.A283T (NLGN4X)] in four different unrelated patients have been identified by PCR and direct sequencing. These four missense variations were absent in the 453 controls and have not been reported in 1000 Genomes Project. Bioinformatic analysis of the four missense variations revealed that p.G84R and p.A283T were "Probably Damaging". The variations may cause abnormal synaptic homeostasis and therefore trigger the patients more predisposed to autism. By case-control analysis, we identified the common SNPs (rs3747333 and rs3747334) in the NLGN4X gene significantly associated with risk for autism [p = 5.09E-005; OR 4.685 (95% CI 2.073-10.592)]. Our data provided a further evidence for the involvement of NLGN3 and NLGN4X gene in the pathogenesis of autism in Chinese population.

PMID: 24570023 [PubMed - indexed for MEDLINE]

Paroxysmal kinesigenic dyskinesia caused by 16p11.2 microdeletion.

February 11, 2015 - 8:56am

Paroxysmal kinesigenic dyskinesia caused by 16p11.2 microdeletion.

Tremor Other Hyperkinet Mov (N Y). 2014;4:274

Authors: Termsarasab P, Yang AC, Reiner J, Mei H, Scott SA, Frucht SJ

Abstract
BACKGROUND: Four cases of paroxysmal kinesigenic dyskinesia (PKD) have been reported in individuals with proximal 16p11.2 microdeletions that include PRRT2.
CASE REPORT: We describe a fifth patient with PKD, features of Asperger's syndrome, and mild language delays. Sanger sequencing of the PRRT2 gene did not identify any mutations implicated in PKD. However, microarray-based comparative genomic hybridization (aCGH) detected a 533.9-kb deletion on chromosome 16, encompassing over 20 genes and transcripts.
DISCUSSION: This case underscores the importance of aCGH testing for individuals with PKD who do not have PRRT2 mutations, particularly when developmental delays, speech problems, intellectual disability, and/or autism spectrum disorder are present.

PMID: 25667815 [PubMed]

Variants of unknown significance on chromosomal microarray analysis: parental perspectives.

February 11, 2015 - 8:56am

Variants of unknown significance on chromosomal microarray analysis: parental perspectives.

J Community Genet. 2015 Feb 10;

Authors: Jez S, Martin M, South S, Vanzo R, Rothwell E

Abstract
Chromosomal microarray is the recommended first-tier genetic test when a child presents with idiopathic developmental delay (DD), intellectual disability (ID), and/or autism spectrum disorder (ASD). Microarray may discover variants of unknown clinical significance (VUS) and been suggested to cause parental stress and anxiety. A retrospective, mixed methods study investigated parental perceptions of chromosomal microarray results that contain VUS. Surveys were sent to parents of children with DD/ID/ASD following a VUS result to seek information regarding parental understanding of the result, perceived value, and perceptions of child vulnerability and parental stress. Parents reported that chromosomal microarray was important for understanding their child's diagnosis and they were satisfied with the information. A majority of parents reported high confidence in their ability to explain a VUS result to others. Of the parents who reported they received support, many reported that the support was from a genetic counselor. Based on these results, VUS results are important to parents of children with DD/ID/ASD and genetic counseling regarding VUS results contributes positively to both parental understanding and support.

PMID: 25666435 [PubMed - as supplied by publisher]

Cognitive and Neurobehavioral Profile in Boys With Duchenne Muscular Dystrophy.

February 11, 2015 - 8:56am
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Cognitive and Neurobehavioral Profile in Boys With Duchenne Muscular Dystrophy.

J Child Neurol. 2015 Feb 6;

Authors: Banihani R, Smile S, Yoon G, Dupuis A, Mosleh M, Snider A, McAdam L

Abstract
Duchenne muscular dystrophy is a progressive neuromuscular condition that has a high rate of cognitive and learning disabilities as well as neurobehavioral disorders, some of which have been associated with disruption of dystrophin isoforms. Retrospective cohort of 59 boys investigated the cognitive and neurobehavioral profile of boys with Duchenne muscular dystrophy. Full-scale IQ of < 70 was seen in 27%; learning disability in 44%, intellectual disability in 19%; attention-deficit/hyperactivity disorder in 32%; autism spectrum disorders in 15%; and anxiety in 27%. Mutations affecting Dp260 isoform and 5'untranslated region of Dp140 were observed in 60% with learning disability, 50% intellectual disability, 77% with autism spectrum disorders, and 94% with anxiety. No statistically significant correlation was noted between comorbidities and dystrophin isoforms; however, there is a trend of cumulative loss of dystrophin isoforms with declining full-scale IQ. Enhanced psychology testing to include both cognitive and neurobehavioral disorders is recommended for all individuals with Duchenne muscular dystrophy.

PMID: 25660133 [PubMed - as supplied by publisher]

Concise review: Fragile X proteins in stem cell maintenance and differentiation.

February 11, 2015 - 8:56am
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Concise review: Fragile X proteins in stem cell maintenance and differentiation.

Stem Cells. 2014 Jul;32(7):1724-33

Authors: Li Y, Zhao X

Abstract
Fragile X syndrome (FXS), the most common genetic form of autism spectrum disorder, is caused by deficiency of the fragile X mental retardation protein (FMRP). Despite extensive research and scientific progress, understanding how FMRP regulates brain development and function remains a major challenge. FMRP is a neuronal RNA-binding protein that binds about a third of messenger RNAs in the brain and controls their translation, stability, and cellular localization. The absence of FMRP results in increased protein synthesis, leading to enhanced signaling in a number of intracellular pathways, including the mTOR, mGLuR5, ERK, Gsk3β, PI3K, and insulin pathways. Until recently, FXS was largely considered a deficit of mature neurons; however, a number of new studies have shown that FMRP may also play important roles in stem cells, among them neural stem cells, germline stem cells, and pluripotent stem cells. In this review, we will cover these newly discovered functions of FMRP, as well as the other two fragile X-related proteins, in stem cells. We will also discuss the literature on the use of stem cells, particularly neural stem cells and induced pluripotent stem cells, as model systems for studying the functions of FMRP in neuronal development.

PMID: 24648324 [PubMed - indexed for MEDLINE]

Neuronal Tsc1/2 complex controls autophagy through AMPK-dependent regulation of ULK1.

February 11, 2015 - 8:56am
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Neuronal Tsc1/2 complex controls autophagy through AMPK-dependent regulation of ULK1.

Hum Mol Genet. 2014 Jul 15;23(14):3865-74

Authors: Di Nardo A, Wertz MH, Kwiatkowski E, Tsai PT, Leech JD, Greene-Colozzi E, Goto J, Dilsiz P, Talos DM, Clish CB, Kwiatkowski DJ, Sahin M

Abstract
Tuberous sclerosis complex (TSC) is a disorder arising from mutation in the TSC1 or TSC2 gene, characterized by the development of hamartomas in various organs and neurological manifestations including epilepsy, intellectual disability and autism. TSC1/2 protein complex negatively regulates the mammalian target of rapamycin complex 1 (mTORC1) a master regulator of protein synthesis, cell growth and autophagy. Autophagy is a cellular quality-control process that sequesters cytosolic material in double membrane vesicles called autophagosomes and degrades it in autolysosomes. Previous studies in dividing cells have shown that mTORC1 blocks autophagy through inhibition of Unc-51-like-kinase1/2 (ULK1/2). Despite the fact that autophagy plays critical roles in neuronal homeostasis, little is known on the regulation of autophagy in neurons. Here we show that unlike in non-neuronal cells, Tsc2-deficient neurons have increased autolysosome accumulation and autophagic flux despite mTORC1-dependent inhibition of ULK1. Our data demonstrate that loss of Tsc2 results in autophagic activity via AMPK-dependent activation of ULK1. Thus, in Tsc2-knockdown neurons AMPK activation is the dominant regulator of autophagy. Notably, increased AMPK activity and autophagy activation are also found in the brains of Tsc1-conditional mouse models and in cortical tubers resected from TSC patients. Together, our findings indicate that neuronal Tsc1/2 complex activity is required for the coordinated regulation of autophagy by AMPK. By uncovering the autophagy dysfunction associated with Tsc2 loss in neurons, our work sheds light on a previously uncharacterized cellular mechanism that contributes to altered neuronal homeostasis in TSC disease.

PMID: 24599401 [PubMed - indexed for MEDLINE]

Association of genetic variants of GRIN2B with autism.

February 7, 2015 - 8:42am

Association of genetic variants of GRIN2B with autism.

Sci Rep. 2015;5:8296

Authors: Pan Y, Chen J, Guo H, Ou J, Peng Y, Liu Q, Shen Y, Shi L, Liu Y, Xiong Z, Zhu T, Luo S, Hu Z, Zhao J, Xia K

Abstract
Autism (MIM 209850) is a complex neurodevelopmental disorder characterized by social communication impairments and restricted repetitive behaviors. It has a high heritability, although much remains unclear. To evaluate genetic variants of GRIN2B in autism etiology, we performed a system association study of common and rare variants of GRIN2B and autism in cohorts from a Chinese population, involving a total sample of 1,945 subjects. Meta-analysis of a triad family cohort and a case-control cohort identified significant associations of multiple common variants and autism risk (Pmin = 1.73 × 10(-4)). Significantly, the haplotype involved with the top common variants also showed significant association (P = 1.78 × 10(-6)). Sanger sequencing of 275 probands from a triad cohort identified several variants in coding regions, including four common variants and seven rare variants. Two of the common coding variants were located in the autism-related linkage disequilibrium (LD) block, and both were significantly associated with autism (P < 9 × 10(-3)) using an independent control cohort. Burden analysis and case-only analysis of rare coding variants identified by Sanger sequencing did not find this association. Our study for the first time reveals that common variants and related haplotypes of GRIN2B are associated with autism risk.

PMID: 25656819 [PubMed - in process]

Maternal Recall Versus Medical Records of Metabolic Conditions from the Prenatal Period: A Validation Study.

February 7, 2015 - 8:42am

Maternal Recall Versus Medical Records of Metabolic Conditions from the Prenatal Period: A Validation Study.

Matern Child Health J. 2015 Feb 6;

Authors: Krakowiak P, Walker CK, Tancredi DJ, Hertz-Picciotto I

Abstract
To assess validity of maternally-reported diabetes and hypertensive disorders, and reliability of BMI measurements during periconception and pregnancy compared with medical records when mothers are interviewed 2-5 years after delivery. To investigate whether reporting accuracy differed by child's case status (autism, delays, typical development). Participants were mothers of 2-5 year old children with and without neurodevelopmental disorders from the CHARGE (CHildhood Autism Risks from Genetics and the Environment) Study who had both prenatal/delivery records and telephone interviews. Sensitivity and specificity of self-report in telephone interview was assessed by comparison with medical records; agreement was evaluated by kappa statistics. Deviations in reported BMI were evaluated with Bland-Altman plots and concordance correlation coefficient (CCC). Mothers of children with neurodevelopmental disorders (autism or developmental delay) reported metabolic conditions slightly more accurately than control mothers. For diabetes, sensitivity ranged from 73 to 87 % and specificity was ≥98 % across groups. For hypertensive disorders, sensitivity ranged from 57 to 77 % and specificity from 93 to 98 %. Reliability of BMI was high (CCC = 0.930); when grouped into BMI categories, a higher proportion of mothers of delayed children were correctly classified (κwt = 0.93) compared with the autism group and controls (κwt = 0.85 and κwt = 0.84, respectively; P = 0.05). Multiparity was associated with higher discrepancies in BMI and misreporting of hypertensive disorders. For purposes of etiologic studies, self-reported diabetes and hypertensive disorders during periconception and pregnancy show high validity among mothers irrespective of child's case status. Recall of pre-pregnancy BMI is reliable compared with self-reported values in medical records.

PMID: 25656730 [PubMed - as supplied by publisher]

NPAS1 represses the generation of specific subtypes of cortical interneurons.

February 7, 2015 - 8:42am
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NPAS1 represses the generation of specific subtypes of cortical interneurons.

Neuron. 2014 Dec 3;84(5):940-53

Authors: Stanco A, Pla R, Vogt D, Chen Y, Mandal S, Walker J, Hunt RF, Lindtner S, Erdman CA, Pieper AA, Hamilton SP, Xu D, Baraban SC, Rubenstein JL

Abstract
Little is known about genetic mechanisms that regulate the ratio of cortical excitatory and inhibitory neurons. We show that NPAS1 and NPAS3 transcription factors (TFs) are expressed in progenitor domains of the mouse basal ganglia (subpallium, MGE, and CGE). NPAS1(-/-) mutants had increased proliferation, ERK signaling, and expression of Arx in the MGE and CGE. NPAS1(-/-) mutants also had increased neocortical inhibition (sIPSC and mIPSC) and generated an excess of somatostatin(+) (SST) (MGE-derived) and vasoactive intestinal polypeptide(+) (VIP) (CGE-derived) neocortical interneurons, but had a normal density of parvalbumin(+) (PV) (MGE-derived) interneurons. In contrast, NPAS3(-/-) mutants showed decreased proliferation and ERK signaling in progenitors of the ganglionic eminences and had fewer SST(+) and VIP(+) interneurons. NPAS1 repressed activity of an Arx enhancer, and Arx overexpression resulted in increased proliferation of CGE progenitors. These results provide insights into genetic regulation of cortical interneuron numbers and cortical inhibitory tone.

PMID: 25467980 [PubMed - indexed for MEDLINE]

20 ans après: a second mutation in MAOA identified by targeted high-throughput sequencing in a family with altered behavior and cognition.

February 7, 2015 - 8:42am
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20 ans après: a second mutation in MAOA identified by targeted high-throughput sequencing in a family with altered behavior and cognition.

Eur J Hum Genet. 2014 Jun;22(6):776-83

Authors: Piton A, Poquet H, Redin C, Masurel A, Lauer J, Muller J, Thevenon J, Herenger Y, Chancenotte S, Bonnet M, Pinoit JM, Huet F, Thauvin-Robinet C, Jaeger AS, Le Gras S, Jost B, Gérard B, Peoc'h K, Launay JM, Faivre L, Mandel JL

Abstract
Intellectual disability (ID) is characterized by an extraordinary genetic heterogeneity, with >250 genes that have been implicated in monogenic forms of ID. Because this complexity precluded systematic testing for mutations and because clinical features are often non-specific, for some of these genes only few cases or families have been unambiguously documented. It is the case of the X-linked gene encoding monoamine oxidase A (MAOA), for which only one nonsense mutation has been identified in Brunner syndrome, characterized in a single family by mild non-dysmorphic ID and impulsive, violent and aggressive behaviors. We have performed targeted high-throughput sequencing of 220 genes, including MAOA, in patients with undiagnosed ID. We identified a c.797_798delinsTT (p.C266F) missense mutation in MAOA in a boy with autism spectrum disorder, attention deficit and autoaggressive behavior. Two maternal uncles carry the mutation and have severe ID, with a history of maltreatment in early childhood. This novel missense mutation decreases MAOA enzymatic activity, leading to abnormal levels of urinary monoamines. The identification of this new point mutation confirms, for the first time since 1993, the monogenic implication of the MAOA gene in ID of various degrees, autism and behavioral disturbances. The variable expressivity of the mutation observed in male patients of this family may involve gene-environment interactions, and the identification of a perturbation in monoamine metabolism should be taken into account when prescribing psychoactive drugs in such patients.

PMID: 24169519 [PubMed - indexed for MEDLINE]

The role of β3 integrin gene variants in Autism Spectrum Disorders--diagnosis and symptomatology.

February 5, 2015 - 6:57am
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The role of β3 integrin gene variants in Autism Spectrum Disorders--diagnosis and symptomatology.

Gene. 2014 Dec 10;553(1):24-30

Authors: Schuch JB, Muller D, Endres RG, Bosa CA, Longo D, Schuler-Faccini L, Ranzan J, Becker MM, dos Santos Riesgo R, Roman T

Abstract
Autism Spectrum Disorders (ASDs) represent a group of very complex early-onset neurodevelopmental diseases. In this study, we analyzed 5 SNPs (rs2317385, rs5918, rs15908, rs12603582, rs3809865) at the β3 integrin locus (ITGB3), which has been suggested as a possible susceptibility gene, both as single markers and as part of haplotypes in 209 ASD children and their biological parents. We tested for association with the following: a) DSM-IV ASD diagnosis; b) clinical symptoms common in ASD patients (repetitive behaviors, echolalia, seizures and epilepsy, mood instability, aggression, psychomotor agitation, sleep disorders); and c) dimensional scores obtained with the Autism Screening Questionnaire and the Childhood Autism Rating Scale. These hypotheses were investigated using family-based tests, logistic regression models and analysis of covariance. The family-based tests showed an association with the H5 haplotype (composed by GTCGA alleles, the order of SNPs as above), which was transmitted less often than expected by chance (P=0.006; Pcorr=0.036). The analyses of the clinical symptoms showed a trend for an association with rs12603582 (P=0.008; Pcorr=0.064) and positive results for the haplotype composed of rs15908 and rs12603582 (Pglcorr=0.048; Pindcorr=0.015), both in symptoms of echolalia. Other nominal associations with different variants were found and involved epilepsy/seizures, aggression symptoms and higher ASQ scores. Although our positive results are not definitive, they suggest small effect associations of the ITGB3 gene with both ASD diagnosis and symptoms of echolalia. Other studies are nonetheless needed to fully understand the involvement of this locus on the etiology of ASDs and its different clinical aspects.

PMID: 25280596 [PubMed - indexed for MEDLINE]

Fluoxetine for Autistic Behaviors (FAB trial): study protocol for a randomized controlled trial in children and adolescents with autism.

February 5, 2015 - 6:57am
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Fluoxetine for Autistic Behaviors (FAB trial): study protocol for a randomized controlled trial in children and adolescents with autism.

Trials. 2014;15:230

Authors: Mouti A, Reddihough D, Marraffa C, Hazell P, Wray J, Lee K, Kohn M

Abstract
BACKGROUND: Serotonin reuptake inhibitors (SSRIs) are commonly prescribed off-label for children with autism. To date, clinical trials examining the use of SSRIs in autism have been limited by small sample sizes and inconclusive results. The efficacy and safety of SSRIs for moderating autistic behaviors is yet to be adequately examined to provide evidence to support current clinical practice. The aim of the Fluoxetine for Autistic Behaviors (FAB) study is to determine the efficacy and safety of low dose fluoxetine compared with placebo, for reducing the frequency and severity of repetitive stereotypic behaviors in children and adolescents with an autism spectrum disorder (ASD). The relationship between the effectiveness of fluoxetine treatment and serotonin transporter genotype will also be explored.
METHODS/DESIGN: The FAB study is a multicenter, double-blinded, randomized controlled trial, funded by the Australian Government's National Health and Medical Research Council (NHMRC) grant. Participants will be aged between 7.5 and 17 years with a confirmed diagnosis of ASD. Eligible participants will be randomized to either placebo or fluoxetine for a 16-week period. Medication will be titrated over the first four weeks. Reponses to medication will be monitored fortnightly using the Clinical Global Impressions Scale (CGI). The primary outcome measure is the Children's Yale-Brown Obsessive Compulsive Scale-Modified for Pervasive Developmental Disorders (CYBOCS-PDD), administered at baseline and 16 weeks. Secondary outcome measures include the Aberrant Behaviour Scale (ABC), the Spence Children's Anxiety Scale Parent Report (SCAS-P), and the Repetitive Behaviors Scale (RBS-R), measured at baseline and 16 weeks. Participants will be invited to undergo genetic testing for SLC6A4 allele variants using a cheek swab. Continuous outcomes, including the primary outcome will be compared between the active and placebo groups using unadjusted linear regression. Binary outcomes will be compared using unadjusted logistic regression.
DISCUSSION: The FAB study is a large clinical trial to specifically investigate the efficacy of low dose fluoxetine for restricted, repetitive, and stereotyped behaviors in ASD. The outcomes of this study will contribute to evidence-based interventions used in clinical practice to assist children with ASD.
TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry ACTRN12608000173392; registered on 9 April, 2008.

PMID: 24934401 [PubMed - indexed for MEDLINE]

Activity-dependent neuroprotective protein (ADNP) exhibits striking sexual dichotomy impacting on autistic and Alzheimer's pathologies.

February 4, 2015 - 9:02am

Activity-dependent neuroprotective protein (ADNP) exhibits striking sexual dichotomy impacting on autistic and Alzheimer's pathologies.

Transl Psychiatry. 2015;5:e501

Authors: Malishkevich A, Amram N, Hacohen-Kleiman G, Magen I, Giladi E, Gozes I

Abstract
Activity-dependent neuroprotective protein (ADNP) is a most frequent autism spectrum disorder (ASD)-associated gene and the only protein significantly decreasing in the serum of Alzheimer's disease (AD) patients. Is ADNP associated with ASD being more prevalent in boys and AD more prevalent in women? Our results revealed sex-related learning/memory differences in mice, reflecting hippocampal expression changes in ADNP and ADNP-controlled AD/ASD risk genes. Hippocampal ADNP transcript content was doubled in male vs female mice, with females showing equal expression to ADNP haploinsufficient (ADNP(+/)(-)) males and no significant genotype-associated reduction. Increased male ADNP expression was replicated in human postmortem hippocampal samples. The hippocampal transcript for apolipoprotein E (the major risk gene for AD) was doubled in female mice compared with males, and further doubled in the ADNP(+/-) females, contrasting a decrease in ADNP(+/-) males. Previously, overexpression of the eukaryotic translation initiation factor 4E (eIF4E) led to ASD-like phenotype in mice. Here, we identified binding sites on ADNP for eIF4E and co-immunoprecipitation. Furthermore, hippocampal eIF4E expression was specifically increased in young ADNP(+/-) male mice. Behaviorally, ADNP(+/-) male mice exhibited deficiencies in object recognition and social memory compared with ADNP(+/+) mice, while ADNP(+/-) females were partially spared. Contrasting males, which preferred novel over familiar mice, ADNP(+/+) females showed no preference to novel mice and ADNP(+/-) females did not prefer mice over object. ADNP expression, positioned as a master regulator of key ASD and AD risk genes, introduces a novel concept of hippocampal gene-regulated sexual dimorphism and an ADNP(+/-) animal model for translational psychiatry.

PMID: 25646590 [PubMed - as supplied by publisher]

Chromatin immunoprecipitation with fixed animal tissues and preparation for high-throughput sequencing.

February 4, 2015 - 9:02am

Chromatin immunoprecipitation with fixed animal tissues and preparation for high-throughput sequencing.

Cold Spring Harb Protoc. 2015;2015(2):pdb.prot084848

Authors: Cotney JL, Noonan JP

Abstract
Chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) is a powerful method used to identify genome-wide binding patterns of transcription factors and distribution of various histone modifications associated with different chromatin states. In most published studies, ChIP-Seq has been performed on cultured cells grown under controlled conditions, allowing generation of large amounts of material in a homogeneous biological state. Although such studies have provided great insight into the dynamic landscapes of animal genomes, they do not allow the examination of transcription factor binding and chromatin states in adult tissues, developing embryonic structures, or tumors. Such knowledge is critical to understanding the information required to create and maintain a complex biological tissue and to identify noncoding regions of the genome directly involved in tissues affected by complex diseases such as autism. Studying these tissue types with ChIP-Seq can be challenging due to the limited availability of tissues and the lack of complex biological states able to be achieved in culture. These inherent differences require alterations of standard cross-linking and chromatin extraction typically used in cell culture. Here we describe a general approach for using small amounts of animal tissue to perform ChIP-Seq directed at histone modifications and transcription factors. Tissue is homogenized before treatment with formaldehyde to ensure proper cross-linking, and a two-step nuclear isolation is performed to increase extraction of soluble chromatin. Small amounts of soluble chromatin are then used for immunoprecipitation (IP) and prepared for multiplexed high-throughput sequencing.

PMID: 25646502 [PubMed - in process]

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