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López-Garrido MP, Carrascosa-Romero MC, Montero-Hernández M, Ruiz-Almansa J, Sánchez-Sánchez F. Brief Report: Evidence of Autism Spectrum Disorder Caused by a Mutation in ATRX Gene: A Case Report. J Autism Dev Disord 2024; 54:379-388. [PMID: 35593993 DOI: 10.1007/s10803-022-05588-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2022] [Indexed: 11/29/2022]
Abstract
ATRX mutations are commonly associated with alpha-thalassaemia mental retardation syndrome (ATR-X syndrome) with a notable variable expressivity. This X-linked disorder is characterized by intellectual disability (ID) in a higher or lesser degree, in which the alpha-thalassaemia feature is not always present. Other phenotypic manifestations like facial dimorphism, hypotonia, microcephaly, skeletal abnormalities or urogenital malformations have been frequently observed in ATR-X syndrome. Herein, we report a missense ATRX mutation (Thr1621Met) in a patient with an autism spectrum disorder (ASD) diagnosis. Except for ID, no typical signs of ATR-X syndrome were found in the patient. These results confirm the extensive phenotypic variability associated to ATRX mutations and show the involvement of this gene in the ASD.
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Affiliation(s)
- María-Pilar López-Garrido
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | | | - Minerva Montero-Hernández
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | - Jesús Ruiz-Almansa
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | - Francisco Sánchez-Sánchez
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha (UCLM), Albacete, Spain.
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Quesnel KM, Martin-Kenny N, Bérubé NG. A mouse model of ATRX deficiency with cognitive deficits and autistic traits. J Neurodev Disord 2023; 15:39. [PMID: 37957569 PMCID: PMC10644498 DOI: 10.1186/s11689-023-09508-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND ATRX is an ATP-dependent chromatin remodeling protein with essential roles in safeguarding genome integrity and modulating gene expression. Deficiencies in this protein cause ATR-X syndrome, a condition characterized by intellectual disability and an array of developmental abnormalities, including features of autism. Previous studies demonstrated that deleting ATRX in mouse forebrain excitatory neurons postnatally resulted in male-specific memory deficits, but no apparent autistic-like behaviours. METHODS We generated mice with an earlier embryonic deletion of ATRX in forebrain excitatory neurons and characterized their behaviour using a series of memory and autistic-related paradigms. RESULTS We found that mutant mice displayed a broader spectrum of impairments, including fear memory, decreased anxiety-like behaviour, hyperactivity, as well as self-injurious and repetitive grooming. Sex-specific alterations were also observed, including male-specific aggression, sensory gating impairments, and decreased social memory. CONCLUSIONS Collectively, the findings indicate that early developmental abnormalities arising from ATRX deficiency in forebrain excitatory neurons contribute to the presentation of fear memory deficits as well as autistic-like behaviours.
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Affiliation(s)
- Katherine M Quesnel
- Department of Anatomy & Cell Biology, Western University, London, Canada
- Department of Paediatrics, Western University, London, Canada
- Division of Genetics & Development, Children's Health Research Institute, London, ON, Canada
| | - Nicole Martin-Kenny
- Department of Anatomy & Cell Biology, Western University, London, Canada
- Department of Paediatrics, Western University, London, Canada
- Division of Genetics & Development, Children's Health Research Institute, London, ON, Canada
| | - Nathalie G Bérubé
- Department of Anatomy & Cell Biology, Western University, London, Canada.
- Department of Paediatrics, Western University, London, Canada.
- Division of Genetics & Development, Children's Health Research Institute, London, ON, Canada.
- Department of Oncology, Western University, London, Canada.
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3
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Tsompanidis A, Warrier V, Baron-Cohen S. The genetics of autism and steroid-related traits in prenatal and postnatal life. Front Endocrinol (Lausanne) 2023; 14:1126036. [PMID: 37223033 PMCID: PMC10200920 DOI: 10.3389/fendo.2023.1126036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 04/18/2023] [Indexed: 05/25/2023] Open
Abstract
Background Autism likelihood is a largely heritable trait. Autism prevalence has a skewed sex ratio, with males being diagnosed more often than females. Steroid hormones play a mediating role in this, as indicated by studies of both prenatal biology and postnatal medical conditions in autistic men and women. It is currently unclear if the genetics of steroid regulation or production interact with the genetic liability for autism. Methods To address this, two studies were conducted using publicly available datasets, which focused respectively on rare genetic variants linked to autism and neurodevelopmental conditions (study 1) and common genetic variants (study 2) for autism. In Study 1 an enrichment analysis was conducted, between autism-related genes (SFARI database) and genes that are differentially expressed (FDR<0.1) between male and female placentas, in 1st trimester chorionic villi samples of viable pregnancies (n=39). In Study 2 summary statistics of genome wide association studies (GWAS) were used to investigate the genetic correlation between autism and bioactive testosterone, estradiol and postnatal PlGF levels, as well as steroid-related conditions such as polycystic ovaries syndrome (PCOS), age of menarche, and androgenic alopecia. Genetic correlation was calculated based on LD Score regression and results were corrected for multiple testing with FDR. Results In Study 1, there was significant enrichment of X-linked autism genes in male-biased placental genes, independently of gene length (n=5 genes, p<0.001). In Study 2, common genetic variance associated with autism did not correlate to the genetics for the postnatal levels of testosterone, estradiol or PlGF, but was associated with the genotypes associated with early age of menarche in females (b=-0.109, FDR-q=0.004) and protection from androgenic alopecia for males (b=-0.135, FDR-q=0.007). Conclusion The rare genetic variants associated with autism appear to interact with placental sex differences, while the common genetic variants associated with autism appear to be involved in the regulation of steroid-related traits. These lines of evidence indicate that the likelihood for autism is partly linked to factors mediating physiological sex differences throughout development.
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Affiliation(s)
- Alex Tsompanidis
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
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Li L, Cui Z, Wang L. A More Female-Characterized Resting-State Brain: Graph Similarity Analyses of Sex Influence on the Human Brain Intrinsic Functional Network. Brain Topogr 2022; 35:341-351. [PMID: 35499628 DOI: 10.1007/s10548-022-00900-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 12/21/2021] [Indexed: 11/02/2022]
Abstract
It remains unclear whether human species exhibits sexual dimorphism in brain activities, and how the dimorphisms associated with sex-characterized behaviors. Here, in a large dataset from Human Connectome Project, we investigated sex differences of resting-state network structure by using local and global network graph similarity analysis. The "typical male" and "typical female" resting-state networks were highly similar. However, we found significant inter-sex difference in all local brain networks compared with sex-label permutations. The global and many local network topologies showed significant higher intra-female similarity, while males' network topologies were more dissimilar to each other. Additionally, by using global graph similarity analysis, we found that female individuals whose brain network were more similar to the average pattern present lower social-related anger, lower social distress and better companionships, while similar effects were not detected for males. Our study confirms the existence of sex-related resting-state network topology. Female's intrinsic brain is closer to a typical pattern than male's, and they may more fulfill the "similarity breeds connection" principle in building social ties.
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Affiliation(s)
- Leinian Li
- School of Psychology, Shandong Normal University, 250013, Jinan, People's Republic of China
| | - Zhijun Cui
- State Key Lab of Cognitive Neuroscience and Learning, Beijing Normal University, 100088, Beijing, People's Republic of China
| | - Li Wang
- Curriculum and Teaching Materials Research Institution, People's Education Press, 100081, Beijing, People's Republic of China.
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5
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Li J, Ming Z, Yang L, Wang T, Liu G, Ma Q. Long noncoding RNA XIST: Mechanisms for X chromosome inactivation, roles in sex-biased diseases, and therapeutic opportunities. Genes Dis 2022; 9:1478-1492. [PMID: 36157489 PMCID: PMC9485286 DOI: 10.1016/j.gendis.2022.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/16/2022] [Accepted: 04/18/2022] [Indexed: 11/30/2022] Open
Abstract
Sexual dimorphism has been reported in various human diseases including autoimmune diseases, neurological diseases, pulmonary arterial hypertension, and some types of cancers, although the underlying mechanisms remain poorly understood. The long noncoding RNA (lncRNA) X-inactive specific transcript (XIST) is involved in X chromosome inactivation (XCI) in female placental mammals, a process that ensures the balanced expression dosage of X-linked genes between sexes. XIST is abnormally expressed in many sex-biased diseases. In addition, escape from XIST-mediated XCI and skewed XCI also contribute to sex-biased diseases. Therefore, its expression or modification can be regarded as a biomarker for the diagnosis and prognosis of many sex-biased diseases. Genetic manipulation of XIST expression can inhibit the progression of some of these diseases in animal models, and therefore XIST has been proposed as a potential therapeutic target. In this manuscript, we summarize the current knowledge about the mechanisms for XIST-mediated XCI and the roles of XIST in sex-biased diseases, and discuss potential therapeutic strategies targeting XIST.
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Brand BA, Blesson AE, Smith-Hicks CL. The Impact of X-Chromosome Inactivation on Phenotypic Expression of X-Linked Neurodevelopmental Disorders. Brain Sci 2021; 11:brainsci11070904. [PMID: 34356138 PMCID: PMC8305405 DOI: 10.3390/brainsci11070904] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/16/2021] [Accepted: 06/20/2021] [Indexed: 12/20/2022] Open
Abstract
Nearly 20% of genes located on the X chromosome are associated with neurodevelopmental disorders (NDD) due to their expression and role in brain functioning. Given their location, several of these genes are either subject to or can escape X-chromosome inactivation (XCI). The degree to which genes are subject to XCI can influence the NDD phenotype between males and females. We provide a general review of X-linked NDD genes in the context of XCI and detailed discussion of the sex-based differences related to MECP2 and FMR1, two common X-linked causes of NDD that are subject to XCI. Understanding the effects of XCI on phenotypic expression of NDD genes may guide the development of stratification biomarkers in X-linked disorders.
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Affiliation(s)
- Boudewien A Brand
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Alyssa E Blesson
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Constance L. Smith-Hicks
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Correspondence:
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7
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Körber L, Schneider H, Fleischer N, Maier-Wohlfart S. No evidence for preferential X-chromosome inactivation as the main cause of divergent phenotypes in sisters with X-linked hypohidrotic ectodermal dysplasia. Orphanet J Rare Dis 2021; 16:98. [PMID: 33622384 PMCID: PMC7901220 DOI: 10.1186/s13023-021-01735-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/09/2021] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND X-linked hypohidrotic ectodermal dysplasia (XLHED), a rare genetic disorder, affects the normal development of ectodermal derivatives, such as hair, skin, teeth, and sweat glands. It is caused by pathogenic variants of the gene EDA and defined by a triad of hypotrichosis, hypo- or anodontia, and hypo- or anhidrosis which may lead to life-threatening hyperthermia. Although female carriers are less severely affected than male patients, they display symptoms, too, with high phenotypic variability. This study aimed to elucidate whether phenotypic differences in female XLHED patients with identical EDA genotypes might be explained by deviating X-chromosome inactivation (XI) patterns. METHODS Six families, each consisting of two sisters with the same EDA variant and their parents (with either mother or father being carrier of the variant), participated in this study. XLHED-related data like sweating ability, dental status, facial dysmorphism, and skin issues were assessed. We determined the women`s individual XI patterns in peripheral blood leukocytes by the human androgen receptor assay and collated the results with phenotypic features. RESULTS The surprisingly large inter- and intrafamilial variability of symptoms in affected females was not explicable by the pathogenic variants. Our cohort showed no higher rate of nonrandom XI in peripheral blood leukocytes than the general female population. Furthermore, skewed XI patterns in favour of the mutated alleles were not associated with more severe phenotypes. CONCLUSIONS We found no evidence for preferential XI in female XLHED patients and no distinct correlation between XLHED-related phenotypic features and XI patterns. Phenotypic variability seems to be evoked by other genetic or epigenetic factors.
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Affiliation(s)
- Laura Körber
- Center for Ectodermal Dysplasias and Department of Pediatrics, University Hospital Erlangen, Loschgestr. 15, 91054, Erlangen, Germany
| | - Holm Schneider
- Center for Ectodermal Dysplasias and Department of Pediatrics, University Hospital Erlangen, Loschgestr. 15, 91054, Erlangen, Germany
| | | | - Sigrun Maier-Wohlfart
- Center for Ectodermal Dysplasias and Department of Pediatrics, University Hospital Erlangen, Loschgestr. 15, 91054, Erlangen, Germany.
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Wilson HA, Creighton C, Scharfman H, Choleris E, MacLusky NJ. Endocrine Insights into the Pathophysiology of Autism Spectrum Disorder. Neuroscientist 2020; 27:650-667. [PMID: 32912048 DOI: 10.1177/1073858420952046] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Autism spectrum disorder (ASD) is a class of neurodevelopmental disorders that affects males more frequently than females. Numerous genetic and environmental risk factors have been suggested to contribute to the development of ASD. However, no one factor can adequately explain either the frequency of the disorder or the male bias in its prevalence. Gonadal, thyroid, and glucocorticoid hormones all contribute to normal development of the brain, hence perturbations in either their patterns of secretion or their actions may constitute risk factors for ASD. Environmental factors may contribute to ASD etiology by influencing the development of neuroendocrine and neuroimmune systems during early life. Emerging evidence suggests that the placenta may be particularly important as a mediator of the actions of environmental and endocrine risk factors on the developing brain, with the male being particularly sensitive to these effects. Understanding how various risk factors integrate to influence neural development may facilitate a clearer understanding of the etiology of ASD.
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Affiliation(s)
- Hayley A Wilson
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada.,Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Carolyn Creighton
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Helen Scharfman
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, New York University Langone Health, New York, NY, USA.,Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Elena Choleris
- Department of Psychology, University of Guelph, Guelph, Ontario, Canada
| | - Neil J MacLusky
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
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Zhang X, Li Y, Ma L, Zhang G, Liu M, Wang C, Zheng Y, Li R. A new sex-specific underlying mechanism for female schizophrenia: accelerated skewed X chromosome inactivation. Biol Sex Differ 2020; 11:39. [PMID: 32680558 PMCID: PMC7368719 DOI: 10.1186/s13293-020-00315-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 07/02/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND X chromosome inactivation (XCI) is the mechanism by which the X-linked gene dosage is adjusted between the sexes. Evidence shows that many sex-specific diseases have their basis in X chromosome biology. While female schizophrenia patients often have a delayed age of disease onset and clinical phenotypes that are different from those of males, it is unknown whether the sex differences in schizophrenia are associated with X-linked gene dosage and the choice of X chromosome silencing in female cells. Previous studies demonstrated that sex chromosome aneuploidies may be related to the pathogeneses of some psychiatric diseases. Here, we examined the changes in skewed XCI in patients with schizophrenia. METHODS A total of 109 female schizophrenia (SCZ) patients and 80 age- and sex-matched healthy controls (CNTLs) were included in this study. We evaluated clinical features including disease onset age, disease duration, clinical symptoms by the Positive and Negative Syndrome Scale (PANSS) and antipsychotic treatment dosages. The XCI skewing patterns were analyzed by the methylation profile of the HUMARA gene found in DNA isolated from SCZ patient and CNTL leukocytes in the three age groups. RESULTS First, we found that the frequency of skewed XCI in SCZ patients was 4 times more than that in the age- and sex-matched CNTLs (p < 0.01). Second, we found an earlier onset of severe XCI skewing in the SCZ patients than in CNTLs. Third, we demonstrated a close relationship between the severity of skewed XCI and schizophrenic symptoms (PANSS score ≥ 90) as well as the age of disease onset. Fourth, we demonstrated that the skewed XCI in SCZ patients was not transmitted from the patients' mothers. LIMITATIONS The XCI skewing pattern might differ depending on tissues or organs. Although this is the first study to explore skewed XCI in SCZ, in the future, samples from different tissues or cells in SCZ patients might be important for understanding the impact of skewed XCI in this disease. CONCLUSION Our study, for the first time, investigated skewed XCI in female SCZ patients and presented a potential mechanism for the sex differences in SCZ. Our data also suggested that XCI might be a potential target for the development of female-specific interventions for SCZ.
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Affiliation(s)
- Xinzhu Zhang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Yuhong Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Lei Ma
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Guofu Zhang
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Min Liu
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Chuanyue Wang
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Yi Zheng
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Rena Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China. .,The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China.
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10
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Martin-Kenny N, Bérubé NG. Effects of a postnatal Atrx conditional knockout in neurons on autism-like behaviours in male and female mice. J Neurodev Disord 2020; 12:17. [PMID: 32580781 PMCID: PMC7315487 DOI: 10.1186/s11689-020-09319-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 06/04/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Alpha-thalassemia/mental retardation, X-linked, or ATRX, is an autism susceptibility gene that encodes a chromatin remodeler. Mutations of ATRX result in the ATR-X intellectual disability syndrome and have been identified in autism spectrum disorder (ASD) patients. The mechanisms by which ATRX mutations lead to autism and autistic-like behaviours are not yet known. To address this question, we generated mice with postnatal Atrx inactivation in excitatory neurons of the forebrain and performed a battery of behavioural assays that assess autistic-like behaviours. METHODS Male and female mice with a postnatal conditional ablation of ATRX were generated using the Cre/lox system under the control of the αCaMKII gene promoter. These mice were tested in a battery of behavioural tests that assess autistic-like features. We utilized paradigms that measure social behaviour, repetitive, and stereotyped behaviours, as well as sensory gating. Statistics were calculated by two-way repeated measures ANOVA with Sidak's multiple comparison test or unpaired Student's t tests as indicated. RESULTS The behaviour tests revealed no significant differences between Atrx-cKO and control mice. We identified sexually dimorphic changes in odor habituation and discrimination; however, these changes did not correlate with social deficits. CONCLUSION The postnatal knockout of Atrx in forebrain excitatory neurons does not lead to autism-related behaviours in male or female mice.
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Affiliation(s)
- Nicole Martin-Kenny
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Division of Genetics and Development, Children's Health Research Institute, London, Ontario, Canada
| | - Nathalie G Bérubé
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
- Division of Genetics and Development, Children's Health Research Institute, London, Ontario, Canada.
- Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
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Abstract
PURPOSE OF REVIEW Neurodevelopmental disorders disproportionately affect males. The mechanisms underlying male vulnerability or female protection are not known and remain understudied. Determining the processes involved is crucial to understanding the etiology and advancing treatment of neurodevelopmental disorders. Here, we review current findings and theories that contribute to male preponderance of neurodevelopmental disorders, with a focus on autism. RECENT FINDINGS Recent work on the biological basis of the male preponderance of autism and other neurodevelopmental disorders includes discussion of a higher genetic burden in females and sex-specific gene mutations or epigenetic changes that differentially confer risk to males or protection to females. Other mechanisms discussed are sex chromosome and sex hormone involvement. Specifically, fetal testosterone is involved in many aspects of development and may interact with neurotransmitter, neuropeptide, or immune pathways to contribute to male vulnerability. Finally, the possibilities of female underdiagnosis and a multi-hit hypothesis are discussed. This review highlights current theories of male bias in developmental disorders. Topics include environmental, genetic, and epigenetic mechanisms; theories of sex chromosomes, hormones, neuroendocrine, and immune function; underdiagnosis of females; and a multi-hit hypothesis.
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Affiliation(s)
- Sarah L. Ferri
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, IA 52242 USA
| | - Ted Abel
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, IA 52242 USA
| | - Edward S. Brodkin
- Center for Neurobiology and Behavior, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Translational Research Laboratory, 125 South 31 Street, Room 2202, Philadelphia, PA 19104-3403 USA
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Winick-Ng W, Rylett RJ. Into the Fourth Dimension: Dysregulation of Genome Architecture in Aging and Alzheimer's Disease. Front Mol Neurosci 2018. [PMID: 29541020 PMCID: PMC5835833 DOI: 10.3389/fnmol.2018.00060] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by synapse dysfunction and cognitive impairment. Understanding the development and progression of AD is challenging, as the disease is highly complex and multifactorial. Both environmental and genetic factors play a role in AD pathogenesis, highlighted by observations of complex DNA modifications at the single gene level, and by new evidence that also implicates changes in genome architecture in AD patients. The four-dimensional structure of chromatin in space and time is essential for context-dependent regulation of gene expression in post-mitotic neurons. Dysregulation of epigenetic processes have been observed in the aging brain and in patients with AD, though there is not yet agreement on the impact of these changes on transcription. New evidence shows that proteins involved in genome organization have altered expression and localization in the AD brain, suggesting that the genomic landscape may play a critical role in the development of AD. This review discusses the role of the chromatin organizers and epigenetic modifiers in post-mitotic cells, the aging brain, and in the development and progression of AD. How these new insights can be used to help determine disease risk and inform treatment strategies will also be discussed.
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Affiliation(s)
- Warren Winick-Ng
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Molecular Medicine Research Laboratories, Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - R Jane Rylett
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Molecular Medicine Research Laboratories, Robarts Research Institute, University of Western Ontario, London, ON, Canada
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13
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Zhang X, Yang J, Li Y, Ma X, Li R. Sex chromosome abnormalities and psychiatric diseases. Oncotarget 2018; 8:3969-3979. [PMID: 27992373 PMCID: PMC5354807 DOI: 10.18632/oncotarget.13962] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/07/2016] [Indexed: 12/02/2022] Open
Abstract
Excesses of sex chromosome abnormalities in patients with psychiatric diseases have recently been observed. It remains unclear whether sex chromosome abnormalities are related to sex differences in some psychiatric diseases. While studies showed evidence of susceptibility loci over many sex chromosomal regions related to various mental diseases, others demonstrated that the sex chromosome aneuploidies may be the key to exploring the pathogenesis of psychiatric disease. In this review, we will outline the current evidence on the interaction of sex chromosome abnormalities with schizophrenia, autism, ADHD and mood disorders.
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Affiliation(s)
- Xinzhu Zhang
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Jian Yang
- Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Beijing, China
| | - Yuhong Li
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Beijing, China
| | - Xin Ma
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Beijing, China
| | - Rena Li
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Beijing, China.,Center for Hormone Advanced Science and Education, Roskamp Institute, Sarasota, FL, USA
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14
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Forsberg SL, Ilieva M, Maria Michel T. Epigenetics and cerebral organoids: promising directions in autism spectrum disorders. Transl Psychiatry 2018; 8:14. [PMID: 29317608 PMCID: PMC5802583 DOI: 10.1038/s41398-017-0062-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/26/2017] [Indexed: 01/04/2023] Open
Abstract
Autism spectrum disorders (ASD) affect 1 in 68 children in the US according to the Centers for Disease Control and Prevention (CDC). It is characterized by impairments in social interactions and communication, restrictive and repetitive patterns of behaviors, and interests. Owing to disease complexity, only a limited number of treatment options are available mainly for children that alleviate but do not cure the debilitating symptoms. Studies confirm a genetic link, but environmental factors, such as medications, toxins, and maternal infection during pregnancy, as well as birth complications also play a role. Some studies indicate a set of candidate genes with different DNA methylation profiles in ASD compared to healthy individuals. Thus epigenetic alterations could help bridging the gene-environment gap in deciphering the underlying neurobiology of autism. However, epigenome-wide association studies (EWAS) have mainly included a very limited number of postmortem brain samples. Hence, cellular models mimicking brain development in vitro will be of great importance to study the critical epigenetic alterations and when they might happen. This review will give an overview of the state of the art concerning knowledge on epigenetic changes in autism and how new, cutting edge expertise based on three-dimensional (3D) stem cell technology models (brain organoids) can contribute in elucidating the multiple aspects of disease mechanisms.
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Affiliation(s)
- Sheena Louise Forsberg
- Department of Psychiatry, Institute for Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Mirolyuba Ilieva
- Department of Psychiatry, Institute for Clinical Research, University of Southern Denmark, Odense, Denmark.
| | - Tanja Maria Michel
- Department of Psychiatry, Institute for Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Psychiatry, Psychiatry in the region of Southern Denmark, Odense, Denmark
- Odense Center for Applied Neuroscience BRIDGE, University of Southern Denmark, Psychiatry in the Region of Southern Denmark, Odense University Hospital, Odense, Denmark
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15
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Yin J, Schaaf CP. Autism genetics - an overview. Prenat Diagn 2016; 37:14-30. [DOI: 10.1002/pd.4942] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Jiani Yin
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston TX USA
| | - Christian P. Schaaf
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston TX USA
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16
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Dandulakis MG, Meganathan K, Kroll KL, Bonni A, Constantino JN. Complexities of X chromosome inactivation status in female human induced pluripotent stem cells-a brief review and scientific update for autism research. J Neurodev Disord 2016; 8:22. [PMID: 27303449 PMCID: PMC4907282 DOI: 10.1186/s11689-016-9155-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/20/2016] [Indexed: 02/07/2023] Open
Abstract
Induced pluripotent stem cells (iPSCs) allow researchers to make customized patient-derived cell lines by reprogramming noninvasively retrieved somatic cells. These cell lines have the potential to faithfully represent an individual’s genetic background; therefore, in the absence of available human brain tissue from a living patient, these models have a significant advantage relative to other models of neurodevelopmental disease. When using human induced pluripotent stem cells (hiPSCs) to model X-linked developmental disorders or inherited conditions that undergo sex-specific modulation of penetrance (e.g., autism spectrum disorders), there are significant complexities in the course and status of X chromosome inactivation (XCI) that are crucial to consider in establishing the validity of cellular models. There are major gaps and inconsistencies in the existing literature regarding XCI status during the derivation and maintenance of hiPSCs and their differentiation into neurons. Here, we briefly describe the importance of the problem, review the findings and inconsistencies of the existing literature, delineate options for specifying XCI status in clonal populations, and develop recommendations for future studies.
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Affiliation(s)
- Mary G Dandulakis
- School of Medicine, Washington University in St. Louis, St. Louis, USA
| | - Kesavan Meganathan
- Department of Developmental Biology, Washington University in St. Louis, Campus Box 8103, 660 S. Euclid Ave., St. Louis, MO 63110-1093 USA
| | - Kristen L Kroll
- Department of Developmental Biology, Washington University in St. Louis, Campus Box 8103, 660 S. Euclid Ave., St. Louis, MO 63110-1093 USA
| | - Azad Bonni
- Department of Neuroscience, Washington University in St. Louis, Campus Box 8108, 660 S. Euclid Ave., St. Louis, MO 63110-1093 USA
| | - John N Constantino
- Department of Psychiatry, Washington University in St. Louis, Campus Box 8134, 660 S. Euclid Avenue, St. Louis, MO 63110 USA
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17
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Kirkovski M, Enticott PG, Fitzgerald PB. A review of the role of female gender in autism spectrum disorders. J Autism Dev Disord 2014; 43:2584-603. [PMID: 23525974 DOI: 10.1007/s10803-013-1811-1] [Citation(s) in RCA: 208] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This paper reviews the literature exploring gender differences associated with the clinical presentation of autism spectrum disorders (ASD). The potentially mediating effect of comorbid psychopathology, biological and neurodevelopmental implications on these gender differences is also discussed. A vastly heterogeneous condition, while females on the lower-functioning end of the spectrum appear to be more severely affected, an altered clinical manifestation of the disorder among high-functioning females may consequently result in many being un- or mis-diagnosed. To date, there is strong bias in the literature towards the clinical presentation of ASD in males. It is imperative that future research explores gender differences across the autism spectrum, in order to improve researchers', clinicians' and the public's understanding of this debilitating disorder.
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Affiliation(s)
- Melissa Kirkovski
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Level 4, 607 St Kilda Rd, Melbourne, VIC, 3004, Australia,
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18
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Ben-David E, Shohat S, Shifman S. Allelic expression analysis in the brain suggests a role for heterogeneous insults affecting epigenetic processes in autism spectrum disorders. Hum Mol Genet 2014; 23:4111-24. [PMID: 24659497 DOI: 10.1093/hmg/ddu128] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Monoallelic expression, including genomic imprinting, X-chromosome inactivation and random monoallelic expression of autosomal genes are epigenetic phenomena. Genes that are expressed in a monoallelic way may be more vulnerable to genetic or epigenetic mutations. Thus, comprehensive exploration of monoallelic expression in human brains may shed light on complex brain disorders. Autism-related disorders are known to be associated with imprinted genes on chromosome 15. However, it is not clear whether other imprinted regions or other types of monoallelic expression are associated with autism spectrum disorder (ASD). Here, we performed a genome-wide survey of allele expression imbalance (AEI) in the human brain using single-nucleotide polymorphisms (SNPs), in 18 individuals with ASD and 15 controls. Individuals with ASD had the most extreme number of monoallelic expressed SNPs in both the autosomes and the X chromosome. In two cases that were studied in detail, the monoallelic expression was confined to specific brain region or cell type. Using these data, we were also able to define the allelic expression status of known imprinted genes in the human brain and to identify abnormal imprinting in an individual with ASD. Lastly, we developed an analysis of individual-level expression, focusing on the difference of each individual from the mean. We found that individuals with ASD had more genes that were up- or down-regulated in an individual-specific manner. We also identified pathways perturbed in specific individuals. These results underline the heterogeneity in gene regulation in ASD, at the level of both allelic and total expression.
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Affiliation(s)
- Eyal Ben-David
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shahar Shohat
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sagiv Shifman
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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19
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Hall L, Kelley E. The contribution of epigenetics to understanding genetic factors in autism. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2013; 18:872-81. [PMID: 24126868 DOI: 10.1177/1362361313503501] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Autism spectrum disorder is a grouping of neurodevelopmental disorders characterized by deficits in social communication and language, as well as by repetitive and stereotyped behaviors. While the environment is believed to play a role in the development of autism spectrum disorder, there is now strong evidence for a genetic link to autism. Despite such evidence, studies investigating a potential single-gene cause for autism, although insightful, have been highly inconclusive. A consideration of an epigenetic approach proves to be very promising in clarifying genetic factors involved in autism. The present article is intended to provide a review of key findings pertaining to epigenetics in autism in such a way that a broader audience of individuals who do not have a strong background in genetics may better understand this highly specific and scientific content. Epigenetics refers to non-permanent heritable changes that alter expression of genes without altering the DNA sequence itself and considers the role of environment in this modulation of gene expression. This review provides a brief description of epigenetic processes, highlights evidence in the literature of epigenetic dysregulation in autism, and makes use of noteworthy findings to illustrate how a consideration of epigenetic factors can deepen our understanding of the development of autism. Furthermore, this discussion will present a promising new way for moving forward in the investigation of genetic factors within autism.
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20
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Persico AM, Napolioni V. Autism genetics. Behav Brain Res 2013; 251:95-112. [PMID: 23769996 DOI: 10.1016/j.bbr.2013.06.012] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 06/03/2013] [Accepted: 06/04/2013] [Indexed: 12/22/2022]
Abstract
Autism spectrum disorder (ASD) is a severe neuropsychiatric disease with strong genetic underpinnings. However, genetic contributions to autism are extremely heterogeneous, with many different loci underlying the disease to a different extent in different individuals. Moreover, the phenotypic expression (i.e., "penetrance") of these genetic components is also highly variable, ranging from fully penetrant point mutations to polygenic forms with multiple gene-gene and gene-environment interactions. Furthermore, many genes involved in ASD are also involved in intellectual disability, further underscoring their lack of specificity in phenotypic expression. We shall hereby review current knowledge on the genetic basis of ASD, spanning genetic/genomic syndromes associated with autism, monogenic forms due to copy number variants (CNVs) or rare point mutations, mitochondrial forms, and polygenic autisms. Finally, the recent contributions of genome-wide association and whole exome sequencing studies will be highlighted.
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Affiliation(s)
- Antonio M Persico
- Child and Adolescent Neuropsychiatry Unit, University Campus Bio-Medico, Rome, Italy.
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21
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Flores R, Hirota Y, Armstrong B, Sawa A, Tomoda T. DISC1 regulates synaptic vesicle transport via a lithium-sensitive pathway. Neurosci Res 2011; 71:71-7. [PMID: 21664390 PMCID: PMC3156137 DOI: 10.1016/j.neures.2011.05.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/26/2011] [Accepted: 05/24/2011] [Indexed: 12/11/2022]
Abstract
Disrupted-in-Schizophrenia 1 (DISC1) is a susceptibility gene for major mental illnesses, including bipolar disorder and schizophrenia. Although the roles of DISC1 in nervous system development and functions are increasingly recognized, pathophysiological mechanisms underlying a range of neuropsychiatric symptoms caused by DISC1 mutations remain unclear. Here we show that DISC1 enhances synaptic vesicle transport along microtubules. Knocking down DISC1 expression results in attenuated vesicle transport in primary cortical neurons. Likewise, expressing the dominant-negative, breakpoint mutant version of DISC1 causes defective vesicle transport, by disrupting the assembly between the kinesin-1 adaptor FEZ1 and the cargo protein Synaptotagmin-1 (Syt-1). In addition, lithium, a mood-stabilizing agent used for the treatment of bipolar disorder, can restore the assembly of FEZ1 and Syt-1, and normalizes the defective transport caused by the dominant-negative DISC1. Thus, this study addresses a new role of DISC1 in organelle transport in neurons, and suggests that this cellular pathway could be therapeutically targeted for the treatment against neuropsychiatric diseases.
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Affiliation(s)
- Rafael Flores
- Department of Neurosciences, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA
| | - Yuki Hirota
- Department of Neurosciences, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA
| | - Brian Armstrong
- Department of Neurosciences, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA
| | - Akira Sawa
- Department of Psychiatry and Behavioral Sciences, Department of Neuroscience, Johns Hopkins University, 600N, Wolfe St., Baltimore, MD 21287, USA
| | - Toshifumi Tomoda
- Department of Neurosciences, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd., Duarte, CA 91010, USA
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22
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Ben-David E, Granot-Hershkovitz E, Monderer-Rothkoff G, Lerer E, Levi S, Yaari M, Ebstein RP, Yirmiya N, Shifman S. Identification of a functional rare variant in autism using genome-wide screen for monoallelic expression. Hum Mol Genet 2011; 20:3632-41. [PMID: 21680558 DOI: 10.1093/hmg/ddr283] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent work has led to the identification of several susceptibility genes for autism spectrum disorder (ASD) and an increased appreciation of the importance of rare and de novo mutations. Some of the mutations may be very hard to detect using current strategies, especially if they are located in regulatory regions. We present a new approach to identify functional mutations that exploit the fact that many rare mutations disrupt the expression of genes from a single parental chromosome. The method incorporates measurement of the relative expression of the two copies of a gene across the genome using single nucleotide polymorphism arrays. Allelic expression has been successfully used to study common regulatory polymorphisms; however, it has not been implemented as a screening tool for rare mutation. We tested the potential of this approach by screening for monoallelic expression in lymphoblastoid cell lines derived from a small ASD cohort. After filtering regions shared across multiple samples, we identified genes showing monoallelic expression in specific ASD samples. Validation by quantitative sequencing demonstrated that the genes (or only part of them) are monoallelic expressed. The genes included both previously suspected risk factors for ASD and novel candidates. In one gene, named autism susceptibility candidate 2 (AUTS2), we identified a rare duplication that is likely to be the cause of monoallelic expression. Our results demonstrate the ability to identify rare regulatory mutations using genome-wide allelic expression screens, capabilities that could be expanded to other diseases, especially those with suspected involvement of rare dominantly acting mutations.
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Affiliation(s)
- Eyal Ben-David
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem,Edmond J. Safra campus, Jerusalem 91904, Israel
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23
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Baron-Cohen S, Lombardo MV, Auyeung B, Ashwin E, Chakrabarti B, Knickmeyer R. Why are autism spectrum conditions more prevalent in males? PLoS Biol 2011; 9:e1001081. [PMID: 21695109 PMCID: PMC3114757 DOI: 10.1371/journal.pbio.1001081] [Citation(s) in RCA: 417] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Autism Spectrum Conditions (ASC) are much more common in males, a bias that may offer clues to the etiology of this condition. Although the cause of this bias remains a mystery, we argue that it occurs because ASC is an extreme manifestation of the male brain. The extreme male brain (EMB) theory, first proposed in 1997, is an extension of the Empathizing-Systemizing (E-S) theory of typical sex differences that proposes that females on average have a stronger drive to empathize while males on average have a stronger drive to systemize. In this first major update since 2005, we describe some of the evidence relating to the EMB theory of ASC and consider how typical sex differences in brain structure may be relevant to ASC. One possible biological mechanism to account for the male bias is the effect of fetal testosterone (fT). We also consider alternative biological theories, the X and Y chromosome theories, and the reduced autosomal penetrance theory. None of these theories has yet been fully confirmed or refuted, though the weight of evidence in favor of the fT theory is growing from converging sources (longitudinal amniocentesis studies from pregnancy to age 10 years old, current hormone studies, and genetic association studies of SNPs in the sex steroid pathways). Ultimately, as these theories are not mutually exclusive and ASC is multi-factorial, they may help explain the male prevalence of ASC.
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Affiliation(s)
- Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
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24
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Schaaf CP, Sabo A, Sakai Y, Crosby J, Muzny D, Hawes A, Lewis L, Akbar H, Varghese R, Boerwinkle E, Gibbs RA, Zoghbi HY. Oligogenic heterozygosity in individuals with high-functioning autism spectrum disorders. Hum Mol Genet 2011; 20:3366-75. [PMID: 21624971 PMCID: PMC3153303 DOI: 10.1093/hmg/ddr243] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Autism spectrum disorders (ASDs) are a heterogeneous group of neuro-developmental disorders. While significant progress has been made in the identification of genes and copy number variants associated with syndromic autism, little is known to date about the etiology of idiopathic non-syndromic autism. Sanger sequencing of 21 known autism susceptibility genes in 339 individuals with high-functioning, idiopathic ASD revealed de novo mutations in at least one of these genes in 6 of 339 probands (1.8%). Additionally, multiple events of oligogenic heterozygosity were seen, affecting 23 of 339 probands (6.8%). Screening of a control population for novel coding variants in CACNA1C, CDKL5, HOXA1, SHANK3, TSC1, TSC2 and UBE3A by the same sequencing technology revealed that controls were carriers of oligogenic heterozygous events at significantly (P < 0.01) lower rate, suggesting oligogenic heterozygosity as a new potential mechanism in the pathogenesis of ASDs.
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Affiliation(s)
- Christian P Schaaf
- Department of Molecular and Human Genetics, Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
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25
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Chiocchetti A, Pakalapati G, Duketis E, Wiemann S, Poustka A, Poustka F, Klauck SM. Mutation and expression analyses of the ribosomal protein gene RPL10 in an extended German sample of patients with autism spectrum disorder. Am J Med Genet A 2011; 155A:1472-5. [PMID: 21567917 DOI: 10.1002/ajmg.a.33977] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Accepted: 01/22/2011] [Indexed: 11/11/2022]
Affiliation(s)
- A Chiocchetti
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
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26
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Baron-Cohen S, Auyeung B, Ashwin E, Knickmeyer R. Fetal testosterone and autistic traits: A response to three fascinating commentaries. Br J Psychol 2010; 100:39-47. [DOI: 10.1348/000712608x394271] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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28
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Abstract
In this review, we detail the history, molecular diagnosis, epidemiology, and clinical features of the MECP2 duplication syndrome, including considerations for the care of patients with this X-linked neurodevelopmental disorder. MECP2 duplication syndrome is 100% penetrant in affected males and is associated with infantile hypotonia, severe to profound mental retardation, autism or autistic features, poor speech development, recurrent infections, epilepsy, progressive spasticity, and, in some cases, developmental regression. Most of the reported cases are inherited, however, de novo cases have been documented. While carrier females have been reported to be unaffected, more recent research demonstrates that despite normal intelligence, female carriers display a range of neuropsychiatric phenotypes that pre-date the birth of an affected son. Given what we know of the syndrome to date, we propose that genetic testing is warranted in cases of males with infantile hypotonia and in cases of boys with mental retardation and autistic features with or without recurrent infections, progressive spasticity, epilepsy, or developmental regression. We discuss recommendations for clinical management and surveillance as well as the need for further clinical, genotype-phenotype, and molecular studies to assist the patients and their families who are affected by this syndrome.
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Affiliation(s)
- Melissa B Ramocki
- Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA.
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29
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Gender differences in neurodevelopmental disorders: autism and fragile x syndrome. Curr Top Behav Neurosci 2010; 8:209-29. [PMID: 21769728 DOI: 10.1007/7854_2010_96] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Gender is an important factor to consider in understanding the clinical presentation, management, and developmental trajectory of children with neuropsychiatric disorders. While much is known about the clinical and neurobehavioural profiles of boys with neuropsychiatric disorders, surprisingly little is known about girls. The aim of this chapter was to review our understanding of gender by considering the most prevalent childhood onset neuropsychiatric disorders, autism and Fragile X syndrome. This chapter highlights findings which suggest that girls with autism and Fragile X syndrome show some unique differences in cognitive and clinical profiles when compared to boys with these conditions; this may indicate the need for innovative assessment and management approaches which take gender into consideration. Our understanding of how differences emerge in boys and girls with neuropsychiatric disorders is unclear, future research needs to focus on the role of biological maturation rates, sex hormones, and psychosocial factors in order to progress this field.
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30
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Nagarajan RP, Patzel KA, Martin M, Yasui DH, Swanberg SE, Hertz-Picciotto I, Hansen RL, Van de Water J, Pessah IN, Jiang R, Robinson WP, LaSalle JM. MECP2 promoter methylation and X chromosome inactivation in autism. Autism Res 2009; 1:169-78. [PMID: 19132145 DOI: 10.1002/aur.24] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Epigenetic mechanisms have been proposed to play a role in the etiology of autism. This hypothesis is supported by the discovery of increased MECP2 promoter methylation associated with decreased MeCP2 protein expression in autism male brain. To further understand the influence of female X chromosome inactivation (XCI) and neighboring methylation patterns on aberrant MECP2 promoter methylation in autism, multiple methylation analyses were peformed on brain and blood samples from individuals with autism. Bisulfite sequencing analyses of a region 0.6 kb upstream of MECP2 in brain DNA samples revealed an abrupt transition from a highly methylated region in both sexes to a region unmethylated in males and subject to XCI in females. Chromatin immunoprecipitation analysis demonstrated that the CCTC-binding factor (CTCF) bound to this transition region in neuronal cells, consistent with a chromatin boundary at the methylation transition. Male autism brain DNA samples displayed a slight increase in methylation in this transition region, suggesting a possible aberrant spreading of methylation into the MECP2 promoter in autism males across this boundary element. In addition, autistic female brain DNA samples showed evidence for aberrant MECP2 promoter methylation as an increase in the number of bisulfite sequenced clones with undefined XCI status for MECP2 but not androgen receptor (AR). To further investigate the specificity of MECP2 methylation alterations in autism, blood DNA samples from females and mothers of males with autism were also examined for XCI skewing at AR, but no significant increase in XCI skewing was observed compared to controls. These results suggest that the aberrant MECP2 methylation in autism brain DNA samples is due to locus-specific rather than global X chromosome methylation changes.
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Affiliation(s)
- Raman P Nagarajan
- Medical Microbiology and Immunology and Rowe Program in Human Genetics, University of California, Davis, CA 95616, USA
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31
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Possible association between the androgen receptor gene and autism spectrum disorder. Psychoneuroendocrinology 2009; 34:752-61. [PMID: 19167832 DOI: 10.1016/j.psyneuen.2008.12.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 12/09/2008] [Accepted: 12/13/2008] [Indexed: 11/20/2022]
Abstract
Autism is a highly heritable disorder but the specific genes involved remain largely unknown. The higher prevalence of autism in men than in women, in conjunction with a number of other observations, has led to the suggestion that prenatal brain exposure to androgens may be of importance for the development of this condition. Prompted by this hypothesis, we investigated the potential influence of variation in the androgen receptor (AR) gene on the susceptibility for autism. To this end, 267 subjects with autism spectrum disorder and 617 controls were genotyped for three polymorphisms in exon 1 of the AR gene: the CAG repeat, the GGN repeat and the rs6152 SNP. In addition, parents and affected siblings were genotyped for 118 and 32 of the cases, respectively. Case-control comparisons revealed higher prevalence of short CAG alleles as well as of the A allele of the rs6152 SNP in female cases than in controls, but revealed no significant differences with respect to the GGN repeat. Analysis of the 118 families using transmission disequilibrium test, on the other hand, suggested an association with the GGN polymorphism, the rare 20-repeat allele being undertransmitted to male cases and the 23-repeat allele being overtransmitted to female cases. Sequencing of the AR gene in 46 patients revealed no mutations or rare variants. The results lend some support for an influence of the studied polymorphisms on the susceptibility for autism, but argue against the possibility that mutations in the AR gene are common in subjects with this condition.
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32
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Gong X, Delorme R, Fauchereau F, Durand CM, Chaste P, Betancur C, Goubran-Botros H, Nygren G, Anckarsäter H, Rastam M, Gillberg IC, Kopp S, Mouren-Simeoni MC, Gillberg C, Leboyer M, Bourgeron T. An investigation of ribosomal protein L10 gene in autism spectrum disorders. BMC MEDICAL GENETICS 2009; 10:7. [PMID: 19166581 PMCID: PMC2645381 DOI: 10.1186/1471-2350-10-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 01/23/2009] [Indexed: 11/13/2022]
Abstract
Background Autism spectrum disorders (ASD) are severe neurodevelopmental disorders with the male:female ratio of 4:1, implying the contribution of X chromosome genetic factors to the susceptibility of ASD. The ribosomal protein L10 (RPL10) gene, located on chromosome Xq28, codes for a key protein in assembling large ribosomal subunit and protein synthesis. Two non-synonymous mutations of RPL10, L206M and H213Q, were identified in four boys with ASD. Moreover, functional studies of mutant RPL10 in yeast exhibited aberrant ribosomal profiles. These results provided a novel aspect of disease mechanisms for autism – aberrant processes of ribosome biosynthesis and translation. To confirm these initial findings, we re-sequenced RPL10 exons and quantified mRNA transcript level of RPL10 in our samples. Methods 141 individuals with ASD were recruited in this study. All RPL10 exons and flanking junctions were sequenced. Furthermore, mRNA transcript level of RPL10 was quantified in B lymphoblastoid cell lines (BLCL) of 48 patients and 27 controls using the method of SYBR Green quantitative PCR. Two sets of primer pairs were used to quantify the mRNA expression level of RPL10: RPL10-A and RPL10-B. Results No non-synonymous mutations were detected in our cohort. Male controls showed similar transcript level of RPL10 compared with female controls (RPL10-A, U = 81, P = 0.7; RPL10-B, U = 61.5, P = 0.2). We did not observe any significant difference in RPL10 transcript levels between cases and controls (RPL10-A, U = 531, P = 0.2; RPL10-B, U = 607.5, P = 0.7). Conclusion Our results suggest that RPL10 has no major effect on the susceptibility to ASD.
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Affiliation(s)
- Xiaohong Gong
- Human Genetics and Cognitive Functions, CNRS URA 2182 Genes, Synapses and Cognition, Institut Pasteur, Paris, France.
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Lintas C, Persico AM. Autistic phenotypes and genetic testing: state-of-the-art for the clinical geneticist. J Med Genet 2008; 46:1-8. [PMID: 18728070 PMCID: PMC2603481 DOI: 10.1136/jmg.2008.060871] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Autism spectrum disorders represent a group of developmental disorders with strong genetic underpinnings. Several cytogenetic abnormalities or de novo mutations able to cause autism have recently been uncovered. In this study, the literature was reviewed to highlight genotype-phenotype correlations between causal gene mutations or cytogenetic abnormalities and behavioural or morphological phenotypes. Based on this information, a set of practical guidelines is proposed to help clinical geneticists pursue targeted genetic testing for patients with autism whose clinical phenotype is suggestive of a specific genetic or genomic aetiology.
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Affiliation(s)
- C Lintas
- Laboratory of Molecular Psychiatry and Neurogenetics, University Campus Bio-Medico, Via Alvaro del Portillo 21, I-00128 Rome, Italy
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