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Esposito D, Cruciani G, Zaccaro L, Di Carlo E, Spitoni GF, Manti F, Carducci C, Fiori E, Leuzzi V, Pascucci T. A Systematic Review on Autism and Hyperserotonemia: State-of-the-Art, Limitations, and Future Directions. Brain Sci 2024; 14:481. [PMID: 38790459 PMCID: PMC11119126 DOI: 10.3390/brainsci14050481] [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: 04/10/2024] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/26/2024] Open
Abstract
Hyperserotonemia is one of the most studied endophenotypes in autism spectrum disorder (ASD), but there are still no unequivocal results about its causes or biological and behavioral outcomes. This systematic review summarizes the studies investigating the relationship between blood serotonin (5-HT) levels and ASD, comparing diagnostic tools, analytical methods, and clinical outcomes. A literature search on peripheral 5-HT levels and ASD was conducted. In total, 1104 publications were screened, of which 113 entered the present systematic review. Of these, 59 articles reported hyperserotonemia in subjects with ASD, and 26 presented correlations between 5-HT levels and ASD-core clinical outcomes. The 5-HT levels are increased in about half, and correlations between hyperserotonemia and clinical outcomes are detected in a quarter of the studies. The present research highlights a large amount of heterogeneity in this field, ranging from the characterization of ASD and control groups to diagnostic and clinical assessments, from blood sampling procedures to analytical methods, allowing us to delineate critical topics for future studies.
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Affiliation(s)
- Dario Esposito
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185 Rome, Italy; (D.E.); (F.M.)
| | - Gianluca Cruciani
- Department of Dynamic and Clinical Psychology, and Health Studies, Sapienza University of Rome, Via degli Apuli 1, 00185 Rome, Italy; (G.C.); (G.F.S.)
| | - Laura Zaccaro
- Department of Psychology, Sapienza University, Via dei Marsi 78, 00185 Rome, Italy; (L.Z.); (T.P.)
| | - Emanuele Di Carlo
- Department of Experimental Medicine, Sapienza University, Viale del Policlinico 155, 00161 Rome, Italy; (E.D.C.); (C.C.)
| | - Grazia Fernanda Spitoni
- Department of Dynamic and Clinical Psychology, and Health Studies, Sapienza University of Rome, Via degli Apuli 1, 00185 Rome, Italy; (G.C.); (G.F.S.)
- Cognitive and Motor Rehabilitation and Neuroimaging Unit, IRCCS Fondazione Santa Lucia, Via Ardeatina 306-354, 00179 Rome, Italy
| | - Filippo Manti
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185 Rome, Italy; (D.E.); (F.M.)
| | - Claudia Carducci
- Department of Experimental Medicine, Sapienza University, Viale del Policlinico 155, 00161 Rome, Italy; (E.D.C.); (C.C.)
| | - Elena Fiori
- Rome Technopole Foundation, P.le Aldo Moro, 5, 00185 Rome, Italy;
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185 Rome, Italy; (D.E.); (F.M.)
| | - Tiziana Pascucci
- Department of Psychology, Sapienza University, Via dei Marsi 78, 00185 Rome, Italy; (L.Z.); (T.P.)
- Centro “Daniel Bovet”, Sapienza University, P.le Aldo Moro 5, 00185 Rome, Italy
- Fondazione Santa Lucia Istituto di Ricovero e Cura a Carattere Scientifico, Via Ardeatina 306, 00179 Rome, Italy
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Lee SH, Cilz NI, Avram SKW, Cymerblit-Sabba A, Song J, Courey K, Howley A, Cooke ME, Young WS. Stimulation of median raphe terminals in dorsal CA2 reduces social investigation in male mice specifically investigating social stimulus of ovariectomized female mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555504. [PMID: 37693526 PMCID: PMC10491145 DOI: 10.1101/2023.08.30.555504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The cornu ammonis area 2 (CA2) region is essential for social behaviors, especially in social aggression and social memory. Recently, we showed that targeted CA2 stimulation of vasopressin presynaptic fibers from the paraventricular nuclei of hypothalamus strongly enhances social memory in mice. In addition, the CA2 area of the mouse hippocampus receives neuronal inputs from other regions including the septal nuclei, the diagonal bands of Broca, supramammillary nuclei, and median raphe nucleus. However, the functions of these projections have been scarcely investigated. A functional role of median raphe (MR) - CA2 projection is supported by the MR to CA2 projections and 82% reduction of hippocampal serotonin (5-HT) levels following MR lesions. Thus, we investigated the behavioral role of presynaptic fibers from the median raphe nucleus projecting to the dorsal CA2 (dCA2). Here, we demonstrate the optogenetic stimulation of 5-HT projections to dCA2 from the MR do not alter social memory, but instead reduce social interaction. We show that optical stimulation of MR fibers excites interneurons in the stratum radiatum (SR) and stratum lacunosum moleculare (SLM) of CA2 region. Consistent with these observations, we show that bath application of 5-HT increases spontaneous GABA release onto CA2 pyramidal neurons and excites presumed interneurons located in the SR/SLM. This is the first study, to our knowledge, which investigates the direct effect of 5-HT release from terminals onto dCA2 neurons on social behaviors. This highlights the different roles for these inputs (i.e., vasopressin inputs regulating social memory versus serotonin inputs regulating social interaction).
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Affiliation(s)
- Su Hyun Lee
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - Nicholas I. Cilz
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - Sarah K. Williams Avram
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - Adi Cymerblit-Sabba
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - June Song
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - Karis Courey
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - Austin Howley
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - Michaela E. Cooke
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
| | - W. Scott Young
- Section on Neural Gene Expression, National Institute of Mental Health, National Institute of Health, Bethesda, MD, United States
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3
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Stilley SE, Blakely RD. Rare Opportunities for Insights Into Serotonergic Contributions to Brain and Bowel Disorders: Studies of the SERT Ala56 Mouse. Front Cell Neurosci 2021; 15:677563. [PMID: 34149362 PMCID: PMC8210832 DOI: 10.3389/fncel.2021.677563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 04/27/2021] [Indexed: 12/12/2022] Open
Abstract
Altered structure, expression, and regulation of the presynaptic serotonin (5-HT) transporter (SERT) have been associated with multiple neurobehavioral disorders, including mood disorders, obsessive-compulsive disorder (OCD), and autism spectrum disorder (ASD). Opportunities to investigate mechanistic links supporting these associations were spurred with the identification of multiple, rare human SERT coding variants in a study that established a male-specific linkage of ASD to a linkage marker on chromosome 17 which encompassed the location of the SERT gene (SLC6A4). We have explored the most common of these variants, SERT Ala56, in vitro and in vivo. Results support a tonic elevation of 5-HT transport activity in transfected cells and human lymphoblasts by the variant in vitro that leads to an increased 5-HT clearance rate in vivo when studied in the SERT Ala56 mouse model, along with altered sensitivity to SERT regulatory signaling pathways. Importantly, hyperserotonemia, or an elevated whole blood 5-HT, level, was found in SERT Ala56 mice, reproducing a well-replicated trait observed in a significant fraction of ASD subjects. Additionally, we found multiple biochemical, physiological, and behavioral alterations in the SERT Ala56 mice that can be analogized to those observed in ASD and its medical comorbidities. The similarity of the functional impact of the SERT Ala56 variant to the consequences of p38α MAPK activation, ascribed to the induction of a biased conformation of the transporter toward an outward-facing conformation, has resulted in successful efforts to restore normal behavioral and bowel function via pharmacological and genetic p38α MAPK targeting. Moreover, the ability of the inflammatory cytokine IL-1β to enhance SERT activity via a p38α MAPK-dependent pathway suggests that the SERT Ala56 conformation mimics that of a chronic inflammatory state, supporting findings in ASD of elevated inflammatory cytokine levels. In this report, we review studies of the SERT Ala56 variant, discussing opportunities for continued insight into how chronically altered synaptic 5-HT homeostasis can drive reversible, functional perturbations in 5-HT sensitive pathways in the brain and periphery, and how targeting the SERT regulome, particularly through activating pathways such as those involving IL-1β/p38α MAPK, may be of benefit for neurobehavioral disorders, including ASD.
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Affiliation(s)
- Samantha E. Stilley
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Randy D. Blakely
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
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Deza-Araujo YI, Baez-Lugo S, Vuilleumier P, Chocat A, Chételat G, Poisnel G, Klimecki OM. Whole blood serotonin levels in healthy elderly are negatively associated with the functional activity of emotion-related brain regions. Biol Psychol 2021; 160:108051. [PMID: 33592271 DOI: 10.1016/j.biopsycho.2021.108051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/31/2020] [Accepted: 02/09/2021] [Indexed: 11/19/2022]
Abstract
Understanding the role of neuromodulators of socio-affective processing is important to ensure psychological wellbeing during older years. Here, we investigated the link between blood serotonin levels and brain and behavioral responses to emotional information in healthy elderly. A priori regions of interest (ROI) were selected due to their role in emotion processing and their dense serotonergic innervation. Correlation analyses were performed between ROI-specific responses to emotional stimuli and whole blood serotonin levels. We found significant negative associations between serotonin and functional activity for the bilateral insula, dorsal anterior cingulate cortex and subgenual gyrus. No association with behavioral measures survived correction for multiple testing. Our results mirror prior pharmacological and genetic work on the link between serotonin and emotional brain reactivity in younger adults. Given the involvement of serotonin in several age-related changes, our study encourages future research to characterize the role of this neuromodulator in emotion processing across the lifespan.
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Affiliation(s)
- Yacila I Deza-Araujo
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland; Laboratory for Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, Medical School, University of Geneva, Geneva, Switzerland.
| | - Sebastian Baez-Lugo
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland; Laboratory for Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, Medical School, University of Geneva, Geneva, Switzerland
| | - Patrik Vuilleumier
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland; Laboratory for Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, Medical School, University of Geneva, Geneva, Switzerland
| | - Anne Chocat
- Inserm, UMR-S U1237, Université De Caen-Normandie, GIP Cyceron, Caen, France
| | - Gaël Chételat
- Inserm, UMR-S U1237, Université De Caen-Normandie, GIP Cyceron, Caen, France
| | - Géraldine Poisnel
- Inserm, UMR-S U1237, Université De Caen-Normandie, GIP Cyceron, Caen, France
| | - Olga M Klimecki
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland; Clinical Psychology and Behavioral Neuroscience, Faculty of Psychology, Technische Universität Dresden, 01187, Dresden, Germany
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5
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Bond C, Johnson J, Chaudhary V, McCarthy E, McWhorter M, Woehrle N. Perinatal fluoxetine exposure results in social deficits and reduced monoamine oxidase gene expression in mice. Brain Res 2020; 1727:146282. [DOI: 10.1016/j.brainres.2019.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/28/2019] [Accepted: 06/01/2019] [Indexed: 12/27/2022]
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Israelyan N, Margolis KG. Reprint of: Serotonin as a link between the gut-brain-microbiome axis in autism spectrum disorders. Pharmacol Res 2019; 140:115-120. [PMID: 30658882 DOI: 10.1016/j.phrs.2018.12.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Autism-spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent deficits in social communication and repetitive patterns of behavior. ASD is, however, often associated with medical comorbidities and gastrointestinal (GI) dysfunction is among the most common. Studies have demonstrated a correlation between GI dysfunction and the degree of social impairment in ASD. The etiology of GI abnormalities in ASD is unclear, though the association between GI dysfunction and ASD-associated behaviors suggest that overlapping developmental defects in the brain and the intestine and/or a defect in communication between the enteric and central nervous systems (ENS and CNS, respectively), known as the gut-brain axis, could be responsible for the observed phenotypes. Brain-gut abnormalities have been increasingly implicated in several disease processes, including ASD. As a critical modulator of ENS and CNS development and function, serotonin may be a nexus for the gut-brain axis in ASD. This paper reviews the role of serotonin in ASD from the perspective of the ENS. A murine model that has been demonstrated to possess brain, behavioral and GI abnormalities mimicking those seen in ASD harbors the most common serotonin transporter (SERT) based mutation (SERT Ala56) found in children with ASD. Discussion of the gut-brain manifestations in the SERT Ala56 mice, and their correction with developmental administration of a 5-HT4 agonist, are also addressed in conjunction with other future directions for diagnosis and treatment.
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Affiliation(s)
- Narek Israelyan
- Columbia University Vagelos College of Physicians and Surgeons, 630 W 168(th) St, New York, NY, 10032, USA.
| | - Kara Gross Margolis
- Department of Pediatrics, Morgan Stanley Children's Hospital, Columbia University Medical Center, 620 W 168(th) St, New York, NY, 10032, USA.
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7
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Israelyan N, Margolis KG. Serotonin as a link between the gut-brain-microbiome axis in autism spectrum disorders. Pharmacol Res 2018; 132:1-6. [PMID: 29614380 DOI: 10.1016/j.phrs.2018.03.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/09/2018] [Accepted: 03/27/2018] [Indexed: 12/20/2022]
Abstract
Autism-spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent deficits in social communication and repetitive patterns of behavior. ASD is, however, often associated with medical comorbidities and gastrointestinal (GI) dysfunction is among the most common. Studies have demonstrated a correlation between GI dysfunction and the degree of social impairment in ASD. The etiology of GI abnormalities in ASD is unclear, though the association between GI dysfunction and ASD-associated behaviors suggest that overlapping developmental defects in the brain and the intestine and/or a defect in communication between the enteric and central nervous systems (ENS and CNS, respectively), known as the gut-brain axis, could be responsible for the observed phenotypes. Brain-gut abnormalities have been increasingly implicated in several disease processes, including ASD. As a critical modulator of ENS and CNS development and function, serotonin may be a nexus for the gut-brain axis in ASD. This paper reviews the role of serotonin in ASD from the perspective of the ENS. A murine model that has been demonstrated to possess brain, behavioral and GI abnormalities mimicking those seen in ASD harbors the most common serotonin transporter (SERT) based mutation (SERT Ala56) found in children with ASD. Discussion of the gut-brain manifestations in the SERT Ala56 mice, and their correction with developmental administration of a 5-HT4 agonist, are also addressed in conjunction with other future directions for diagnosis and treatment.
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Affiliation(s)
- Narek Israelyan
- Columbia University Vagelos College of Physicians and Surgeons, 630 W 168(th) St, New York, NY, 10032, USA.
| | - Kara Gross Margolis
- Department of Pediatrics, Morgan Stanley Children's Hospital, Columbia University Medical Center, 620 W 168(th) St, New York, NY, 10032, USA.
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8
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Shuffrey LC, Guter SJ, Delaney S, Jacob S, Anderson GM, Sutcliffe JS, Cook EH, Veenstra-VanderWeele J. Is there sexual dimorphism of hyperserotonemia in autism spectrum disorder? Autism Res 2017; 10:1417-1423. [PMID: 28401654 DOI: 10.1002/aur.1791] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/30/2017] [Accepted: 03/10/2017] [Indexed: 12/19/2022]
Abstract
Approximately 30% of individuals with autism spectrum disorder (ASD) have elevated whole blood serotonin (5-HT) levels. Genetic linkage and association studies of ASD and of whole blood 5-HT levels as a quantitative trait have revealed sexual dimorphism. Few studies have examined the presence of a sex difference on hyperserotonemia within ASD. To assess whether the rate of hyperserotonemia is different in males than in females with ASD, we measured whole blood 5-HT levels in 292 children and adolescents with ASD, the largest sample in which this biomarker has been assessed. Based upon previous work suggesting that hyperserotonemia is more common prior to puberty, we focused our analysis on the 182 pre-pubertal children with ASD. 42% of pre-pubertal participants were within the hyperserotonemia range. In this population, we found that males were significantly more likely to manifest hyperserotonemia than females (P = 0.03). As expected, no significant difference was found in the post-pubertal population. Additional work will be needed to replicate this intriguing finding and to understand whether it could potentially explain differences in patterns of ASD risk between males and females. Autism Res 2017, 10: 1417-1423. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.
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Affiliation(s)
- Lauren C Shuffrey
- Department of Psychiatry, Columbia University Medical Center, New York.,New York State Psychiatric Institute, New York.,New York-Presbyterian Hospital, Center for Autism and the Developing Brain, New York.,Teachers College, Columbia University, New York
| | - Stephen J Guter
- Institute for Juvenile Research, Department of Psychiatry, University of Illinois at Chicago, Chicago
| | - Shannon Delaney
- Department of Psychiatry, Columbia University Medical Center, New York.,New York State Psychiatric Institute, New York
| | - Suma Jacob
- Department of Psychiatry, University of Minnesota, Minneapolis
| | | | - James S Sutcliffe
- Department of Molecular Physiology and Biophysics, Department of Psychiatry, Vanderbilt University Medical Center, Nashville
| | - Edwin H Cook
- Institute for Juvenile Research, Department of Psychiatry, University of Illinois at Chicago, Chicago
| | - Jeremy Veenstra-VanderWeele
- Department of Psychiatry, Columbia University Medical Center, New York.,New York State Psychiatric Institute, New York.,New York-Presbyterian Hospital, Center for Autism and the Developing Brain, New York
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9
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Zamzow RM, Ferguson BJ, Ragsdale AS, Lewis ML, Beversdorf DQ. Effects of acute beta-adrenergic antagonism on verbal problem solving in autism spectrum disorder and exploration of treatment response markers. J Clin Exp Neuropsychol 2016; 39:596-606. [PMID: 27841098 DOI: 10.1080/13803395.2016.1252724] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Autism spectrum disorder (ASD) is characterized by impairments in social communication as well as restricted, repetitive behaviors. Evidence suggests that some individuals with ASD have cognitive impairments related to weak central coherence and hyperrestricted processing. Reducing noradrenergic activity may improve aspects of network processing and thus improve cognitive abilities, such as verbal problem solving, in individuals with ASD. The present pilot study explores the effects of acute administration of the beta-adrenergic antagonist propranolol on verbal problem solving in adults and adolescents with ASD. In a within-subject crossover-design, 20 participants with ASD received a single dose of propranolol or placebo on one of two sessions in a double-blinded, counterbalanced manner. Verbal problem solving was assessed via an anagram task. Baseline measurements of autonomic nervous system functioning were obtained, and anxiety was assessed at baseline and following drug administration. Participants solved the anagrams more quickly in the propranolol condition, as compared to the placebo condition, suggesting a potential cognitive benefit of this agent. Additionally, we observed a negative linear relationship between response to propranolol on the anagram task and two measures of baseline autonomic activity, as well as a positive linear relationship between drug response and baseline anxiety. These relationships propose potential markers for treatment response, as propranolol influences both autonomic functioning and anxiety. Further investigation is needed to expand on the present single-dose psychopharmacological challenge and explore the observed effects of propranolol in a serial-dose setting.
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Affiliation(s)
- Rachel M Zamzow
- a Interdisciplinary Neuroscience Program , University of Missouri , Columbia , MO , USA
| | - Bradley J Ferguson
- a Interdisciplinary Neuroscience Program , University of Missouri , Columbia , MO , USA
| | - Alexandra S Ragsdale
- b Department of Biological Sciences , University of Missouri , Columbia , MO , USA
| | - Morgan L Lewis
- b Department of Biological Sciences , University of Missouri , Columbia , MO , USA.,c Department of Psychological Sciences , University of Missouri , Columbia , MO , USA
| | - David Q Beversdorf
- c Department of Psychological Sciences , University of Missouri , Columbia , MO , USA.,d Departments of Radiology and Neurology , University of Missouri , Columbia , MO , USA
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10
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Muller CL, Anacker AMJ, Veenstra-VanderWeele J. The serotonin system in autism spectrum disorder: From biomarker to animal models. Neuroscience 2016; 321:24-41. [PMID: 26577932 PMCID: PMC4824539 DOI: 10.1016/j.neuroscience.2015.11.010] [Citation(s) in RCA: 308] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 10/26/2015] [Accepted: 11/04/2015] [Indexed: 02/02/2023]
Abstract
Elevated whole blood serotonin, or hyperserotonemia, was the first biomarker identified in autism spectrum disorder (ASD) and is present in more than 25% of affected children. The serotonin system is a logical candidate for involvement in ASD due to its pleiotropic role across multiple brain systems both dynamically and across development. Tantalizing clues connect this peripheral biomarker with changes in brain and behavior in ASD, but the contribution of the serotonin system to ASD pathophysiology remains incompletely understood. Studies of whole blood serotonin levels in ASD and in a large founder population indicate greater heritability than for the disorder itself and suggest an association with recurrence risk. Emerging data from both neuroimaging and postmortem samples also indicate changes in the brain serotonin system in ASD. Genetic linkage and association studies of both whole blood serotonin levels and of ASD risk point to the chromosomal region containing the serotonin transporter (SERT) gene in males but not in females. In ASD families with evidence of linkage to this region, multiple rare SERT amino acid variants lead to a convergent increase in serotonin uptake in cell models. A knock-in mouse model of one of these variants, SERT Gly56Ala, recapitulates the hyperserotonemia biomarker and shows increased brain serotonin clearance, increased serotonin receptor sensitivity, and altered social, communication, and repetitive behaviors. Data from other rodent models also suggest an important role for the serotonin system in social behavior, in cognitive flexibility, and in sensory development. Recent work indicates that reciprocal interactions between serotonin and other systems, such as oxytocin, may be particularly important for social behavior. Collectively, these data point to the serotonin system as a prime candidate for treatment development in a subgroup of children defined by a robust, heritable biomarker.
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Affiliation(s)
- C L Muller
- Vanderbilt Brain Institute, Vanderbilt University, 465 21st Avenue South, Nashville, TN 37232, USA.
| | - A M J Anacker
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, Mail Unit 78, New York, NY 10032, USA.
| | - J Veenstra-VanderWeele
- Sackler Institute for Developmental Psychobiology, Department of Psychiatry, Columbia University; Center for Autism and the Developing Brain, New York Presbyterian Hospital; New York State Psychiatric Institute, 1051 Riverside Drive, Mail Unit 78, New York, NY 10032, USA.
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11
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The serotonin-N-acetylserotonin-melatonin pathway as a biomarker for autism spectrum disorders. Transl Psychiatry 2014; 4:e479. [PMID: 25386956 PMCID: PMC4259991 DOI: 10.1038/tp.2014.120] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/21/2014] [Accepted: 10/05/2014] [Indexed: 12/27/2022] Open
Abstract
Elevated whole-blood serotonin and decreased plasma melatonin (a circadian synchronizer hormone that derives from serotonin) have been reported independently in patients with autism spectrum disorders (ASDs). Here, we explored, in parallel, serotonin, melatonin and the intermediate N-acetylserotonin (NAS) in a large cohort of patients with ASD and their relatives. We then investigated the clinical correlates of these biochemical parameters. Whole-blood serotonin, platelet NAS and plasma melatonin were assessed in 278 patients with ASD, their 506 first-degree relatives (129 unaffected siblings, 199 mothers and 178 fathers) and 416 sex- and age-matched controls. We confirmed the previously reported hyperserotonemia in ASD (40% (35-46%) of patients), as well as the deficit in melatonin (51% (45-57%)), taking as a threshold the 95th or 5th percentile of the control group, respectively. In addition, this study reveals an increase of NAS (47% (41-54%) of patients) in platelets, pointing to a disruption of the serotonin-NAS-melatonin pathway in ASD. Biochemical impairments were also observed in the first-degree relatives of patients. A score combining impairments of serotonin, NAS and melatonin distinguished between patients and controls with a sensitivity of 80% and a specificity of 85%. In patients the melatonin deficit was only significantly associated with insomnia. Impairments of melatonin synthesis in ASD may be linked with decreased 14-3-3 proteins. Although ASDs are highly heterogeneous, disruption of the serotonin-NAS-melatonin pathway is a very frequent trait in patients and may represent a useful biomarker for a large subgroup of individuals with ASD.
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12
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Francis SM, Sagar A, Levin-Decanini T, Liu W, Carter CS, Jacob S. Oxytocin and vasopressin systems in genetic syndromes and neurodevelopmental disorders. Brain Res 2014; 1580:199-218. [PMID: 24462936 PMCID: PMC4305432 DOI: 10.1016/j.brainres.2014.01.021] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/08/2013] [Accepted: 01/15/2014] [Indexed: 10/25/2022]
Abstract
Oxytocin (OT) and arginine vasopressin (AVP) are two small, related neuropeptide hormones found in many mammalian species, including humans. Dysregulation of these neuropeptides have been associated with changes in behavior, especially social interactions. We review how the OT and AVP systems have been investigated in Autism Spectrum Disorder (ASD), Prader-Willi Syndrome (PWS), Williams Syndrome (WS) and Fragile X syndrome (FXS). All of these neurodevelopmental disorders (NDD) are marked by social deficits. While PWS, WS and FXS have identified genetic mutations, ASD stems from multiple genes with complex interactions. Animal models of NDD are invaluable for studying the role and relatedness of OT and AVP in the developing brain. We present data from a FXS mouse model affecting the fragile X mental retardation 1 (Fmr1) gene, resulting in decreased OT and AVP staining cells in some brain regions. Reviewing the research about OT and AVP in these NDD suggests that altered OT pathways may be downstream from different etiological factors and perturbations in development. This has implications for ongoing studies of the therapeutic application of OT in NDD. This article is part of a Special Issue entitled Oxytocin and Social Behav.
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Affiliation(s)
- S M Francis
- University of Minnesota, Department of Psychiatry, Minneapolis, MN, USA
| | - A Sagar
- University of California at Irvine, Department of Psychiatry and Human Behavior, USA
| | - T Levin-Decanini
- University of Minnesota, Department of Psychiatry, Minneapolis, MN, USA
| | - W Liu
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - C S Carter
- University of North Carolina, Department of Psychiatry, Chapel Hill, NC, USA
| | - S Jacob
- University of Minnesota, Department of Psychiatry, Minneapolis, MN, USA.
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Gabriele S, Sacco R, Persico AM. Blood serotonin levels in autism spectrum disorder: a systematic review and meta-analysis. Eur Neuropsychopharmacol 2014; 24:919-29. [PMID: 24613076 DOI: 10.1016/j.euroneuro.2014.02.004] [Citation(s) in RCA: 201] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 01/09/2014] [Accepted: 02/12/2014] [Indexed: 12/14/2022]
Abstract
Elevated blood serotonin (5-HT) levels were the first biomarker identified in autism research. Many studies have contrasted blood 5-HT levels in autistic patients and controls, but different measurement protocols, technologies, and biomaterials have been used through the years. We performed a systematic review and meta-analysis to provide an overall estimate of effect size and between-study heterogeneity, while verifying whether and to what extent different methodological approaches influence the strength of this association. Our literature search strategy identified 551 papers, from which 22 studies providing patient and control blood 5-HT values were selected for meta-analysis. Significantly higher 5-HT levels in autistic patients compared to controls were recorded both in whole blood (WB) [O.R.=4.6; (3.1-5.2); P=1.0×10(-12]), and in platelet-rich plasma (PRP) [O.R.=2.6 (1.8-3.9); P=2.7×10(-7)]. Predictably, studies measuring 5-HT levels in platelet-poor plasma (PPP) yielded no significant group difference [O.R.=0.54 (0.2-2-0); P=0.36]. Altogether, elevated 5-HT blood levels were recorded in 28.3% in WB and 22.5% in PRP samples of autistic individuals, as reported in 15 and 4 studies, respectively. Studies employing HPLC vs fluorometric assays yield similar cumulative effect sizes, but the former display much lower variability. In summary, despite some limitations mainly due to small study sample sizes, our results significantly reinforce the reliability of elevated 5-HT blood levels as a biomarker in ASD, providing practical indications potentially useful for its inclusion in multi-marker diagnostic panels for clinical use.
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Affiliation(s)
- Stefano Gabriele
- Unit of Child and Adolescent NeuroPsychiatry, Laboratory of Molecular Psychiatry and Neurogenetics, University "Campus Bio-Medico", Via Alvaro del Portillo 21, I-00128 Rome, Italy; Department of Experimental Neurosciences, I.R.C.C.S. "Fondazione Santa Lucia", Rome, Italy
| | - Roberto Sacco
- Unit of Child and Adolescent NeuroPsychiatry, Laboratory of Molecular Psychiatry and Neurogenetics, University "Campus Bio-Medico", Via Alvaro del Portillo 21, I-00128 Rome, Italy; Department of Experimental Neurosciences, I.R.C.C.S. "Fondazione Santa Lucia", Rome, Italy
| | - Antonio M Persico
- Unit of Child and Adolescent NeuroPsychiatry, Laboratory of Molecular Psychiatry and Neurogenetics, University "Campus Bio-Medico", Via Alvaro del Portillo 21, I-00128 Rome, Italy; Department of Experimental Neurosciences, I.R.C.C.S. "Fondazione Santa Lucia", Rome, Italy; Mafalda Luce Center for Pervasive Developmental Disorders, Milan, Italy.
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14
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The need for a comprehensive molecular characterization of autism spectrum disorders. Int J Neuropsychopharmacol 2014; 17:651-73. [PMID: 24229490 DOI: 10.1017/s146114571300117x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Autism spectrum disorders (ASD) are a heterogeneous group of disorders which have complex behavioural phenotypes. Although ASD is a highly heritable neuropsychiatric disorder, genetic research alone has not provided a profound understanding of the underlying causes. Recent developments using biochemical tools such as transcriptomics, proteomics and cellular models, will pave the way to gain new insights into the underlying pathological pathways. This review addresses the state-of-the-art in the search for molecular biomarkers for ASD. In particular, the most important findings in the biochemical field are highlighted and the need for establishing streamlined interaction between behavioural studies, genetics and proteomics is stressed. Eventually, these approaches will lead to suitable translational ASD models and, therefore, a better disease understanding which may facilitate novel drug discovery efforts in this challenging field.
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15
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Weiss LA. Autism genetics: emerging data from genome-wide copy-number and single nucleotide polymorphism scans. Expert Rev Mol Diagn 2014; 9:795-803. [DOI: 10.1586/erm.09.59] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Levin-Decanini T, Maltman N, Francis SM, Guter S, Anderson GM, Cook E, Jacob S. Parental broader autism subphenotypes in ASD affected families: relationship to gender, child's symptoms, SSRI treatment, and platelet serotonin. Autism Res 2013; 6:621-30. [PMID: 23956104 DOI: 10.1002/aur.1322] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 07/04/2013] [Indexed: 02/06/2023]
Abstract
Relationships between parental broader autism phenotype (BAP) scores, gender, selective serotonin reuptake inhibitor (SSRI) treatment, serotonin (5HT) levels, and the child's symptoms were investigated in a family study of autism spectrum disorder (ASD). The Broader Autism Phenotype Questionnaire (BAPQ) was used to measure the BAP of 275 parents. Fathers not taking SSRIs (F-SSRI; n = 115) scored significantly higher on BAP Total and Aloof subscales compared to mothers not receiving treatment (M-SSRI; n = 136.) However, mothers taking SSRIs (M + SSRI; n = 19) scored higher than those not taking medication on BAP Total and Rigid subscales, and they were more likely to be BAPQ Total, Aloof, and Rigid positive. Significant correlations were noted between proband autism symptoms and parental BAPQ scores such that Total, Aloof, and Rigid subscale scores of F-SSRI correlated with proband restricted repetitive behavior (RRB) measures on the ADOS, CRI, and RBS-R. However, only the Aloof subscale score of M + SSRI correlated with proband RRB on the ADOS. The correlation between the BAPQ scores of mothers taking SSRIs and child scores, as well as the increase in BAPQ scores of this group of mothers, requires careful interpretation and further study because correlations would not withstand multiple corrections. As expected by previous research, significant parent-child correlations were observed for 5HT levels. However, 5HT levels were not correlated with behavioral measures. Study results suggest that the expression of the BAP varies not only across parental gender, but also across individuals using psychotropic medication and those who do not.
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Affiliation(s)
| | - N Maltman
- Department of Psychiatry, University of Illinois at Chicago, IL
| | - S M Francis
- Department of Psychiatry, University of Illinois at Chicago, IL
| | - S Guter
- Department of Psychiatry, University of Illinois at Chicago, IL
| | - G M Anderson
- Departments of Child Psychiatry and Laboratory Medicine at Yale University School of Medicine, New Haven, CT
| | - E Cook
- Department of Psychiatry, University of Illinois at Chicago, IL
| | - S Jacob
- Department of Psychiatry, University of Illinois at Chicago, IL
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17
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Oblak A, Gibbs TT, Blatt GJ. Reduced serotonin receptor subtypes in a limbic and a neocortical region in autism. Autism Res 2013; 6:571-83. [PMID: 23894004 DOI: 10.1002/aur.1317] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 06/17/2013] [Indexed: 11/09/2022]
Abstract
Autism is a behaviorally defined, neurological disorder with symptom onset before the age of 3. Abnormalities in social-emotional behaviors are a core deficit in autism, and are characterized by impaired reciprocal-social interaction, lack of facial expressions, and the inability to recognize familiar faces. The posterior cingulate cortex (PCC) and fusiform gyrus (FG) are two regions within an extensive limbic-cortical network that contribute to social-emotional behaviors. Evidence indicates that changes in brains of individuals with autism begin prenatally. Serotonin (5-HT) is one of the earliest expressed neurotransmitters, and plays an important role in synaptogenesis, neurite outgrowth, and neuronal migration. Abnormalities in 5-HT systems have been implicated in several psychiatric disorders, including autism, as evidenced by immunology, imaging, genetics, pharmacotherapy, and neuropathology. Although information is known regarding peripheral 5-HT in autism, there is emerging evidence that 5-HT systems in the central nervous system, including various 5-HT receptor subtypes and transporters, are affected in autism. The present study demonstrated significant reductions in 5-HT1A receptor-binding density in superficial and deep layers of the PCC and FG, and in the density of 5-HT(2A) receptors in superficial layers of the PCC and FG. A significant reduction in the density of serotonin transporters (5-HTT) was also found in the deep layers of the FG, but normal levels were demonstrated in both layers of the PCC and superficial layers of the FG. This study provides potential substrates for decreased 5-HT modulation/innervation in the autism brain, and implicate two 5-HT receptor subtypes as potential neuromarkers for novel or existing pharmacotherapies.
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Affiliation(s)
- Adrian Oblak
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts
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18
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Hammock E, Veenstra-VanderWeele J, Yan Z, Kerr TM, Morris M, Anderson GM, Carter CS, Cook EH, Jacob S. Examining autism spectrum disorders by biomarkers: example from the oxytocin and serotonin systems. J Am Acad Child Adolesc Psychiatry 2012; 51:712-721.e1. [PMID: 22721594 PMCID: PMC3672055 DOI: 10.1016/j.jaac.2012.04.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 04/16/2012] [Accepted: 04/25/2012] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Autism spectrum disorder (ASD) is a heritable but highly heterogeneous neuropsychiatric syndrome, which poses challenges for research relying solely on behavioral symptoms or diagnosis. Examining biomarkers may give us ways to identify individuals who demonstrate specific developmental trajectories and etiological factors related to ASD. Plasma oxytocin (OT) and whole-blood serotonin (5-HT) levels are consistently altered in some individuals with ASD. Reciprocal relationships have been described between brain oxytocin and serotonin systems during development. We therefore investigated the relationship between these peripheral biomarkers as well as their relationships with age. METHOD In our first study, we analyzed correlations between these two biomarkers in 31 children and adolescents who were diagnosed with autism and were not on medications. In our second study, we explored whether whole-blood 5-HT levels are altered in mice lacking the oxytocin receptor gene Oxtr. RESULTS In humans, OT and 5-HT were negatively correlated with each other (p < .05) and this relationship was most prominent in children less than 11 years old. Paralleling human findings, mice lacking Oxtr showed increased whole-blood 5-HT levels (p = .05), with this effect driven exclusively by mice less than 4 months old (p < .01). CONCLUSIONS Identifying relationships between identified ASD biomarkers may be a useful approach to connect otherwise disparate findings that span multiple systems in this heterogeneous disorder. Using neurochemical biomarkers to perform parallel studies in animal and human populations within a developmental context is a plausible approach to probe the root causes of ASD and to identify potential interventions.
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Affiliation(s)
- Elizabeth Hammock
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN, USA
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19
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Anderson CJ, Colombo J, Unruh KE. Pupil and salivary indicators of autonomic dysfunction in autism spectrum disorder. Dev Psychobiol 2012; 55:465-82. [PMID: 22644965 DOI: 10.1002/dev.21051] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 05/02/2012] [Indexed: 02/03/2023]
Abstract
Dysregulated tonic pupil size has been reported in autism spectrum disorder (ASD). Among the possible sources of this dysregulation are disruptions in the feedback loop between norepinephrine (NE) and hypothalamic systems. In the current study, we examined afternoon levels of salivary alpha-amylase (sAA, a putative correlate of NE) and cortisol (used to assess stress-based responses) in two independent samples of children with ASD. We found a larger pupil size and lower sAA levels in ASD, compared to typical and clinical age-matched controls. This was substantiated at the individual level, as sAA levels were strongly correlated with tonic pupil size. Relatively little diurnal variation in sAA taken in the home environment in the ASD group was also observed, while typical controls showed a significant linear increase throughout the day. Results are discussed in terms of potential early biomarkers and the elucidation of underlying neural dysfunction in ASD.
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Affiliation(s)
- Christa J Anderson
- Life Span Institute, Neurocognitive Development of Autism Research Laboratory, The University of Kansas, 1000 Sunnyside Avenue, Room 1052, Lawrence, KS 66045, USA.
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20
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Carter MD, Shah CR, Muller CL, Crawley JN, Carneiro AMD, Veenstra-VanderWeele J. Absence of preference for social novelty and increased grooming in integrin β3 knockout mice: initial studies and future directions. Autism Res 2011; 4:57-67. [PMID: 21254450 PMCID: PMC3073711 DOI: 10.1002/aur.180] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 12/09/2010] [Indexed: 12/17/2022]
Abstract
Elevated whole blood serotonin 5-HT, or hyperserotonemia, is a common biomarker in autism spectrum disorder (ASD). The integrin β3 receptor subunit gene (ITGB3) is a quantitative trait locus for whole blood 5-HT levels. Recent work shows that integrin β3 interacts with the serotonin transporter (SERT) in both platelets and in the midbrain. Furthermore, multiple studies have now reported gene-gene interaction between the integrin β3 and SERT genes in association with ASD. Given the lack of previous data on the impact of integrin β3 on brain or behavioral phenotypes, we sought to compare mice with decreased or absent expression of the integrin β3 receptor subunit (Itgb3 +/- and -/-) with wildtype littermate controls in behavioral tasks relevant to ASD. These mice did not show deficits in activity level in the open field or anxiety-like behavior on the elevated plus maze, two potential confounds in the evaluation of mouse social behavior. In the three-chamber social test, mice lacking integrin β3 were shown to have normal sociability but did not show a preference for social novelty. Importantly, the absence of integrin β3 did not impair olfaction or the ability to recall familiar social odors. Additionally, mice lacking integrin β3 showed increased grooming behavior in novel environments. These preliminary studies reveal altered social and repetitive behavior in these mice, which suggests that the integrin β3 subunit may be involved in brain systems relevant to ASD. Further work is needed to fully characterize these behavioral changes and the underlying brain mechanisms.
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Affiliation(s)
- Michelle D. Carter
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA, 37232
| | - Charisma R. Shah
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA, 37232
| | | | - Jacqueline N. Crawley
- Laboratory of Behavioral Neuroscience, National Institute of Mental Health, NIH Building 35 Room 1C-903, Bethesda, MD 20892
| | - Ana M. D. Carneiro
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA, 37232
- Kennedy Center for Research on Human Development, 465 21 Ave S, 7158 MRB III, Vanderbilt University, Nashville, TN, USA, 37232
| | - Jeremy Veenstra-VanderWeele
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA, 37232
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA, 37232
- Department of Pediatrics, Vanderbilt University, Nashville, TN, USA, 37232
- Center for Molecular Neuroscience, Vanderbilt University, Nashville, TN, USA, 37232
- Kennedy Center for Research on Human Development, 465 21 Ave S, 7158 MRB III, Vanderbilt University, Nashville, TN, USA, 37232
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21
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Napolioni V, Lombardi F, Sacco R, Curatolo P, Manzi B, Alessandrelli R, Militerni R, Bravaccio C, Lenti C, Saccani M, Schneider C, Melmed R, Pascucci T, Puglisi-Allegra S, Reichelt KL, Rousseau F, Lewin P, Persico AM. Family-based association study of ITGB3 in autism spectrum disorder and its endophenotypes. Eur J Hum Genet 2010; 19:353-9. [PMID: 21102624 DOI: 10.1038/ejhg.2010.180] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The integrin-β 3 gene (ITGB3), located on human chromosome 17q21.3, was previously identified as a quantitative trait locus (QTL) for 5-HT blood levels and has been implicated as a candidate gene for autism spectrum disorder (ASD). We performed a family-based association study in 281 simplex and 12 multiplex Caucasian families. ITGB3 haplotypes are significantly associated with autism (HBAT, global P=0.038). Haplotype H3 is largely over-transmitted to the affected offspring and doubles the risk of an ASD diagnosis (HBAT P=0.005; odds ratio (OR)=2.000), at the expense of haplotype H1, which is under-transmitted (HBAT P=0.018; OR=0.725). These two common haplotypes differ only at rs12603582 located in intron 11, which reaches a P-value of 0.072 in single-marker FBAT analyses. Interestingly, rs12603582 is strongly associated with pre-term delivery in our ASD patients (P=0.008). On the other hand, it is SNP rs2317385, located at the 5' end of the gene, that significantly affects 5-HT blood levels (Mann-Whitney U-test, P=0.001; multiple regression analysis, P=0.010). No gene-gene interaction between ITGB3 and SLC6A4 has been detected. In conclusion, we identify a significant association between a common ITGB3 haplotype and ASD. Distinct markers, located toward the 5' and 3' ends of the gene, seemingly modulate 5-HT blood levels and autism liability, respectively. Our results also raise interest into ITGB3 influences on feto-maternal immune interactions in autism.
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Affiliation(s)
- Valerio Napolioni
- Laboratory of Molecular Psychiatry and Neurogenetics, University Campus Bio-Medico, Rome, Italy
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22
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Autism in adults. New biologicial findings and their translational implications to the cost of clinical services. Brain Res 2010; 1380:22-33. [PMID: 20969835 DOI: 10.1016/j.brainres.2010.10.042] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/22/2010] [Accepted: 10/13/2010] [Indexed: 11/21/2022]
Abstract
There is increasing evidence that children with autism spectrum disorder (ASD) have differences in brain growth trajectory. However, the neurobiological basis of ASD in adults is poorly understood. We report evidence that brain anatomy and aging in people with ASD is significantly different as compared to controls-so that in adulthood they no longer have a significantly larger overall brain volume, but they do have anatomical and functional abnormalities in frontal lobe, basal ganglia and the limbic system. Further we present preliminary evidence that females have significantly greater abnormalities in brain than males to express the same symptom severity of ASD (i.e. the female brain is "protective" against developing ASD). Also we present preliminary evidence that, in adults, clinical services for autism in the United Kingdom are experiencing very significantly increased demand; but that just over 50% of people seeking a diagnosis from one expert service do not have ASD. This consumes very significant health care resources, and so we need to identify new cost-effective methods to aid current diagnostic practice. We present initial evidence offering proof of concept that brain anatomy can be used to accurately distinguish adults with autism from healthy controls, and from some other neurodevelopmental disorders (ADHD). Hence further studies are required to determine if sMRI can become an aid to current diagnostic practice in young adults with ASD. Lastly we report evidence that differences in serotonin, glutamate and GABA may partially explain neuroanatomical and neurofunctional abnormalities in people with ASD, and that genetic influences on brain maturation vary across the lifespan (with 5-HT transporter polymorphisms having significant modulatory effects in children but not adults).
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23
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Taurines R, Dudley E, Conner AC, Grassl J, Jans T, Guderian F, Mehler-Wex C, Warnke A, Gerlach M, Thome J. Serum protein profiling and proteomics in autistic spectrum disorder using magnetic bead-assisted mass spectrometry. Eur Arch Psychiatry Clin Neurosci 2010; 260:249-55. [PMID: 19784855 DOI: 10.1007/s00406-009-0066-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 09/15/2009] [Indexed: 10/20/2022]
Abstract
The pathophysiology of autistic spectrum disorder (ASD) is not fully understood and there are no diagnostic or predictive biomarkers. Proteomic profiling has been used in the past for biomarker research in several non-psychiatric and psychiatric disorders and could provide new insights, potentially presenting a useful tool for generating such biomarkers in autism. Serum protein pre-fractionation with C8-magnetic beads and protein profiling by matrix-assisted laser desorption/ionisation-time of flight-mass spectrometry (MALDI-ToF-MS) were used to identify possible differences in protein profiles in patients and controls. Serum was obtained from 16 patients (aged 8-18) and age-matched controls. Three peaks in the MALDI-ToF-MS significantly differentiated the ASD sample from the control group. Sub-grouping the ASD patients into children with and without comorbid Attention Deficit and Hyperactivity Disorder, ADHD (ASD/ADHD+ patients, n = 9; ASD/ADHD- patients, n = 7), one peak distinguished the ASD/ADHD+ patients from controls and ASD/ADHD- patients. Our results suggest that altered protein levels in peripheral blood of patients with ASD might represent useful biomarkers for this devastating psychiatric disorder.
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Affiliation(s)
- Regina Taurines
- Academic Unit of Psychiatry, Institute of Life Science, The School of Medicine, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
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24
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Rout UK, Clausen P. Common increase of GATA-3 level in PC-12 cells by three teratogens causing autism spectrum disorders. Neurosci Res 2009; 64:162-9. [DOI: 10.1016/j.neures.2009.02.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 02/19/2009] [Accepted: 02/23/2009] [Indexed: 01/17/2023]
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Davis LK, Hazlett HC, Librant AL, Nopoulos P, Sheffield VC, Piven J, Wassink TH. Cortical enlargement in autism is associated with a functional VNTR in the monoamine oxidase A gene. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:1145-51. [PMID: 18361446 PMCID: PMC2752707 DOI: 10.1002/ajmg.b.30738] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Monoamine oxidase A (MAOA) is an enzyme expressed in the brain that metabolizes dopamine, norepinephrine, epinephrine, and serotonin. Abnormalities of serotonin neurotransmission have long been implicated in the psychopathology of autism. A polymorphism exists within the promoter region of the MAOA gene that influences MAOA expression levels so that "low activity" alleles are associated with increased neurotransmitter levels in the brain. Individuals with autism often exhibit elevated serotonin levels. Additional studies indicate that the "low activity" allele may be associated with lower IQ and more severe autistic symptoms. In this study we genotyped the MAOA promoter polymorphism in a group of 29 males (age 2-3 years) with autism and a group of 39 healthy pediatric controls for whom brain MRI data was available. We found a consistent association between the "low activity" allele and larger brain volumes for regions of the cortex in children with autism but not in controls. We did not find evidence for over-transmission of the "low activity" allele in a separate sample of 114 affected sib pair families. Nor did we find any unknown SNPs in yet another sample of 96 probands. Future studies will determine if there is a more severe clinical phenotype associated with both the "low activity" genotype and the larger brain volumes in our sample.
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Affiliation(s)
- Lea K. Davis
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa,Correspondence to: Lea K. Davis, BS, 4181 Medical Education Research Facility, 375 Newton Road, Iowa City, IA 52242.
| | - Heather C. Hazlett
- Neurodevelopmental Disorders Research Center and Department of Psychiatry, University of North Carolina, Chapel Hill, North Carolina
| | - Amy L. Librant
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Peggy Nopoulos
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Val C. Sheffield
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa,The Howard Hughes Medical Institute, Iowa City, Iowa
| | - Joesph Piven
- Neurodevelopmental Disorders Research Center and Department of Psychiatry, University of North Carolina, Chapel Hill, North Carolina
| | - Thomas H. Wassink
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa
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26
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Anitha A, Nakamura K, Yamada K, Suda S, Thanseem I, Tsujii M, Iwayama Y, Hattori E, Toyota T, Miyachi T, Iwata Y, Suzuki K, Matsuzaki H, Kawai M, Sekine Y, Tsuchiya K, Sugihara GI, Ouchi Y, Sugiyama T, Koizumi K, Higashida H, Takei N, Yoshikawa T, Mori N. Genetic analyses of roundabout (ROBO) axon guidance receptors in autism. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:1019-27. [PMID: 18270976 DOI: 10.1002/ajmg.b.30697] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Autism is a pervasive developmental disorder diagnosed in early childhood. Abnormalities of serotonergic neurotransmission have been reported in autism. Serotonin transporter (SERT) modulates serotonin levels, and is a major therapeutic target in autism. Factors that regulate SERT expression might be implicated in the pathophysiology of autism. One candidate SERT regulatory protein is the roundabout axon guidance molecule, ROBO. SerT expression in Drosophila is regulated by robo; it plays a vital role in mammalian neurodevelopment also. Here, we examined the associations of ROBO3 and ROBO4 with autism, in a trio association study using DNA from 252 families recruited to AGRE. Four SNPs of ROBO3 (rs3923890, P = 0.023; rs7925879, P = 0.017; rs4606490, P = 0.033; and rs3802905, P = 0.049) and a single SNP of ROBO4 (rs6590109, P = 0.009) showed associations with autism; the A/A genotype of rs3923890 showed lower ADI-R_A scores, which reflect social interaction. Significant haplotype associations were also observed for ROBO3 and ROBO4. We further compared the mRNA expressions of ROBO1, ROBO2, ROBO3, and ROBO4 in the lymphocytes of 19 drug-naïve autistic patients and 20 age- and sex-matched controls. Expressions of ROBO1 (P = 0.018) and ROBO2 (P = 0.023) were significantly reduced in the autistic group; the possibility of using the altered expressions of ROBO as peripheral markers for autism, may be explored. In conclusion, we suggest a possible role of ROBO in the pathogenesis of autism. Abnormalities of ROBO may lead to autism either by interfering with serotonergic system, or by disrupting neurodevelopment. To the best of our knowledge, this is the first report relating ROBO with autism.
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Affiliation(s)
- A Anitha
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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27
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Caras ML, MacKenzie K, Rodwin B, Katz DB. Investigating the motivational mechanism of altered saline consumption following 5-HT(1A) manipulation. Behav Neurosci 2008; 122:407-15. [PMID: 18410179 DOI: 10.1037/0735-7044.122.2.407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The precise role played by serotonin (5-HT) in taste--an issue of great interest given the involvement of serotonin in human sensory and eating disorders--is a matter of considerable debate, perhaps because of the variety of methodologies that have been brought to bear by different researchers. Here, we use multiple methods to reveal the motivational mechanism whereby 5-HT(1A) receptor activation modulates drinking behavior. Subcutaneous injections of the selective 5-HT(1A) agonist 8-hydroxy-2-di-n-propylamino-tetralin (8-OH-DPAT), a drug that reduces 5-HT release by acting on presynaptic autoreceptors, dose-dependently increased consumption of 0.45 M NaCl in a one-bottle test. In a two-bottle test, however, 8-OH-DPAT-treated animals (30 microg/kg/ml) demonstrated decreased NaCl preference--although our detection of this effect was obscured by adaptation to the drug across days. Rats' performance in a brief access test confirmed that 8-OH-DPAT decreased preference for saline by both increasing water consumption and decreasing NaCl consumption. Finally, taste reactivity tests demonstrated that the latter result does not reflect decreased NaCl palatability. Overall, the results suggest that 8-OH-DPAT-induced 5-HT hypofunction increases thirst without substantially affecting the palatability of NaCl.
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Affiliation(s)
- Melissa L Caras
- Program in Neuroscience, Brandeis University, Waltham, MA 02454, USA
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Parikh MS, Kolevzon A, Hollander E. Psychopharmacology of aggression in children and adolescents with autism: a critical review of efficacy and tolerability. J Child Adolesc Psychopharmacol 2008; 18:157-78. [PMID: 18439113 DOI: 10.1089/cap.2007.0041] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Autism is characterized by a clinical triad of symptoms that affect social, language, and behavioral domains. Aggression and self-injury may be associated symptoms of autism and can result in significant harm to those affected as well as marked distress for their families. The precise nature of the relationship between aggressive or self-injurious behavior (SIB) and autism remains unclear and as a result, these symptoms are treated with a broad range of pharmacological approaches. This review seeks to systematically and critically examine the evidence for the pharmacological management of aggression and SIB in children with autism spectrum disorders. METHOD The entire PubMed database was searched for English language biomedical articles on clinical trials with medication in autism spectrum disorders. Studies were selected based on the following inclusion criteria: (1) randomized placebo-controlled trials; (2) a sample population that included children and adolescents; (3) at least one standardized assessment of aggression as a primary outcome measure of the study. RESULTS Twenty one trials with 12 medications were identified. Five medications produced significant improvement as compared to placebo, including tianeptine, methylphenidate, risperidone, clonidine, and naltrexone. Only risperidone and methylphenidate demonstrate results that have been replicated across at least two studies. CONCLUSIONS Although many medications have been studied under placebo-controlled conditions, few produce significant improvement. Additional placebo-controlled trials are needed to increase the number of therapeutic options available in the treatment of aggression in autism.
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Affiliation(s)
- Mihir S Parikh
- Mount Sinai School of Medicine, New York, New York 10029, USA
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Lim JE, Pinsonneault J, Sadee W, Saffen D. Tryptophan hydroxylase 2 (TPH2) haplotypes predict levels of TPH2 mRNA expression in human pons. Mol Psychiatry 2007; 12:491-501. [PMID: 17453063 DOI: 10.1038/sj.mp.4001923] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Tryptophan hydroxylase isoform 2 (TPH2) is expressed in serotonergic neurons in the raphe nuclei, where it catalyzes the rate-limiting step in the synthesis of the neurotransmitter serotonin. In search for functional polymorphisms within the TPH2 gene locus, we measured allele-specific expression of TPH2 mRNA in sections of human pons containing the dorsal and median raphe nuclei. Differences in allelic mRNA expression--referred to as allelic expression imbalance (AEI)--are a measure of cis-acting regulation of gene expression and mRNA processing. Two marker SNPs, located in exons 7 and 9 of TPH2 (rs7305115 and rs4290270, respectively), served for quantitative allelic mRNA measurements in pons RNA samples from 27 individuals heterozygous for one or both SNPs. Significant AEI (ranging from 1.2- to 2.5-fold) was detected in 19 out of the 27 samples, implying the presence of cis-acting polymorphisms that differentially affect TPH2 mRNA levels in pons. For individuals heterozygous for both marker SNPs, the results correlated well (r=0.93), validating the AEI analysis. AEI is tightly associated with the exon 7 marker SNP, in 17 of 18 subjects. Remarkably, expression from the minor allele exceeded that of the major allele in each case, possibly representing a gain-of-function. Genotyping of 20 additional TPH2 SNPs identified a haplotype block of five tightly linked SNPs for which heterozygosity is highly correlated with AEI and overall expression of TPH2 mRNA. These results reveal the presence of a functional cis-acting polymorphism, with high frequency in normal human subjects, resulting in increased TPH2 expression levels. The SNPs that correlate with AEI are closely linked to TPH2 SNPs previously shown to associate with major depression and suicide.
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Affiliation(s)
- J-E Lim
- Department of Pharmacology, The Ohio State University, Columbus, OH 43210, USA
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Abstract
Autism is a strongly genetic disorder, with an estimated heritability of greater than 90%. A combination of phenotypic heterogeneity and the likely involvement of multiple interacting loci have hampered efforts at gene discovery. As a consequence, the genetic etiology of the spectrum of autism related disorders remains largely unknown. Over the past several years, the convergence of rapidly advancing genomic technologies, the completion of the human genome project, and increasingly successful collaborative efforts to increase the number of patients available for study have led to the first solid clues to the biological origins of these disorders. This paper will review the literature to date summarizing the results of linkage, cytogenetic, and candidate gene studies with a focus on recent progress. In addition, promising avenues for future research are considered.
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Affiliation(s)
- Abha R Gupta
- Child Study Center, Yale University School of Medicine, New Haven, CT 06520, USA
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Weiss LA, Ober C, Cook EH. ITGB3 shows genetic and expression interaction with SLC6A4. Hum Genet 2006; 120:93-100. [PMID: 16721604 DOI: 10.1007/s00439-006-0196-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2006] [Accepted: 04/09/2006] [Indexed: 10/24/2022]
Abstract
Autism affects more males than females and is associated with disturbances of the serotonin system. The integrin beta3 (ITGB3) and serotonin transporter (SLC6A4) genes were both recently identified as male quantitative trait loci (QTLs) for serotonin levels and alleles of each have been associated with autism. Here, we use publicly available genomic resources to determine whether regulation of expression level could be the mechanism behind association between serotonin level and noncoding variation in ITGB3. We also examine whether ITGB3 might interact with SLC6A4 to contribute to autism susceptibility. Using murine and human expression data, we observe that ITGB3 and SLC6A4 expression levels are correlated (0.38<r<0.78). Moreover, genetic variation in ITGB3 is associated with expression of both ITGB3 (P=0.012) and SLC6A4 (P=0.008) in unrelated CEPH individuals. We also show preliminary evidence that genotypes at the ITGB3 and SLC6A4 loci may interact to affect autism susceptibility (P=0.033).
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Affiliation(s)
- Lauren A Weiss
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA.
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Weiss LA, Kosova G, Delahanty RJ, Jiang L, Cook EH, Ober C, Sutcliffe JS. Variation in ITGB3 is associated with whole-blood serotonin level and autism susceptibility. Eur J Hum Genet 2006; 14:923-31. [PMID: 16724005 DOI: 10.1038/sj.ejhg.5201644] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Autism is a pervasive developmental disorder affecting more males than females. Heritability estimates for autism can rise above 90%, and genes influencing the serotonin system are strong candidates for autism susceptibility genes, as drugs selectively acting on the serotonin system are some of the most effective treatments for maladaptive behaviors seen in autism. ITGB3 was recently identified as a male quantitative trait locus (QTL) for whole-blood serotonin levels in the Hutterites (P = 0.0003). Here, we demonstrate associations between variation in ITGB3 and serotonin levels in two outbred samples (P = 0.010 and 0.015). Lastly, we show that a coding variant of ITGB3 is associated with autism susceptibility in a large multiplex sample (P = 0.00082), and that this variation has different effects in males and females (P = 0.0018).
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Affiliation(s)
- Lauren A Weiss
- Department of Human Genetics, The University of Chicago, Chicago, IL, USA
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Guerini FR, Manca S, Sotgiu S, Tremolada S, Zanzottera M, Agliardi C, Zanetta L, Saresella M, Mancuso R, De Silvestri A, Fois ML, Arru G, Ferrante P. A family based linkage analysis of HLA and 5-HTTLPR gene polymorphisms in Sardinian children with autism spectrum disorder. Hum Immunol 2006; 67:108-17. [PMID: 16698432 DOI: 10.1016/j.humimm.2006.02.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Indexed: 11/22/2022]
Abstract
Autism spectrum disorders (ASD) are characterized by a broad range in clinical presentation. Although a definite genetic cause has not yet been fully demonstrated, family based studies suggest that a multigenic pattern may be responsible for susceptibility, but most results are conflicting and have yet to be replicated. The purpose of this investigation was to analyze the linkage of the human leukocyte antigen (HLA) and the human serotonin transporter coding (5-HTTLPR) genes with ASD in a group of 37 families of Sardinian ethnicity in insular Italy. In 50% of these families, ASD is linked to HLA, and in the other 50% it is linked to 5-HTTLPR polymorphic genes; in other words, linkage to one or the other was evident in all cases. Despite a very homogenous genetic pattern being generally reported for Sardinians, the linkage observed with HLA and 5-HTTLPR genetic regions indicated a statistically defined heterogeneity (p=0.002). No allelic HLA or 5-HTTLPR polymorphisms were specifically associated with ASD, suggesting these loci as markers of other genes mapped in their close proximity that may be more directly involved and thus may merit further analytical studies.
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Affiliation(s)
- Franca R Guerini
- Laboratory of Molecular Medicine and Biotechnologies, Don C. Gnocchi Foundation IRCCS, S. Maria Nascente, Milan, Italy
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Coon H. Current perspectives on the genetic analysis of autism. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2006; 142C:24-32. [PMID: 16419097 DOI: 10.1002/ajmg.c.30079] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Although no definitive genetic mutations leading to autism susceptibility have been established, the field has many new resources to tackle this difficult problem. Numbers of families at many research sites are now large, and new collaborations among these groups will allow for collections of subjects with enough statistical power to detect relatively small gene effects. New technological advances in genotyping will allow for more fine-grained genetic analysis, and more sophisticated techniques have been developed to address the vast amounts of data acquired. Researchers have also begun to focus on intermediate phenotypes associated with autism, such as elevated serotonin, increased head circumference, social difficulties, or language impairment or delay. These phenotypes may help to stratify affected cases into more genetically homogeneous subgroups, and may also occur in their clinically unaffected relatives. The study of intermediate phenotypes may allow investigators to find common gene variants that lead to autism susceptibility. Here we discuss the major intermediate phenotypes, and give an overview of current genetic analysis techniques.
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Affiliation(s)
- Hilary Coon
- Utah Autism Research Program, University of Utah, 421 Wakara Way, Salt Lake City, UT 84108, USA.
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Chandana SR, Behen ME, Juhász C, Muzik O, Rothermel RD, Mangner TJ, Chakraborty PK, Chugani HT, Chugani DC. Significance of abnormalities in developmental trajectory and asymmetry of cortical serotonin synthesis in autism. Int J Dev Neurosci 2005; 23:171-82. [PMID: 15749243 DOI: 10.1016/j.ijdevneu.2004.08.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2004] [Revised: 08/04/2004] [Accepted: 08/05/2004] [Indexed: 11/21/2022] Open
Abstract
The role of serotonin in prenatal and postnatal brain development is well documented in the animal literature. In earlier studies using positron emission tomography (PET) with the tracer alpha[(11)C]methyl-l-tryptophan (AMT), we reported global and focal abnormalities of serotonin synthesis in children with autism. In the present study, we measured brain serotonin synthesis in a large group of autistic children (n = 117) with AMT PET and related these neuroimaging data to handedness and language function. Cortical AMT uptake abnormalities were objectively derived from small homotopic cortical regions using a predefined cutoff asymmetry threshold (>2 S.D. of normal asymmetry). Autistic children demonstrated several patterns of abnormal cortical involvement, including right cortical, left cortical, and absence of abnormal asymmetry. Global brain values for serotonin synthesis capacity (unidirectional uptake rate constant, K-complex) values were plotted as a function of age. K-complex values of autistic children with asymmetry or no asymmetry in cortical AMT uptake followed different developmental patterns, compared to that of a control group of non-autistic children. The autism groups, defined by presence or absence and side of cortical asymmetry, differed on a measure of language as well as handedness. Autistic children with left cortical AMT decreases showed a higher prevalence of severe language impairment, whereas those with right cortical decreases showed a higher prevalence of left and mixed handedness. Global as well as focal abnormally asymmetric development in the serotonergic system could lead to miswiring of the neural circuits specifying hemispheric specialization.
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Affiliation(s)
- Sreenivasa R Chandana
- Department of Pharmacology, Wayne State University School of Medicine, 3901 Beaubian Blvd., Detroit, MI 48201, USA
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Coon H, Dunn D, Lainhart J, Miller J, Hamil C, Battaglia A, Tancredi R, Leppert MF, Weiss R, McMahon W. Possible association between autism and variants in the brain-expressed tryptophan hydroxylase gene (TPH2). Am J Med Genet B Neuropsychiatr Genet 2005; 135B:42-6. [PMID: 15768392 DOI: 10.1002/ajmg.b.30168] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We report a possible association between autism in our sample and a recently described brain-expressed tryptophan hydroxylase gene (TPH2). The well-replicated involvement of the serotonin neurotransmitter system in autism has stimulated interest in many genes in the serotonin pathway as possible candidates for mutations leading to autism susceptibility. Serotonin synthesis is controlled by the rate-limiting enzyme tryptophan hydroxylase. A mouse study of the original tryptophan hydroxylase gene (TPH1) and the new isoform (TPH2) showed that while TPH1 is primarily expressed peripherally, TPH2 is found exclusively in brain tissue. We searched for human sequence variants in 6,467 nucleotides covering all 11 exons of TPH2, and also 248 nucleotides upstream of the start codon, and 935 nucleotides downstream of the stop codon. Eighteen variants were characterized in 88 subjects with autism studied at our two centers, and 95 unrelated control subjects. Using a model-free association method and empirical P value estimation, two variants showed frequency differences between autism and control subjects (P = 0.01 for a T-G variant in intron 1, and P = 0.02 for a A-T variant in intron 4). A haplotype including these variants showed slightly increased significance (P = 0.005). Further investigation of clinical phenotypes showed a possible association between presence of the variants at these two SNPs and higher scores on the Autism Diagnostic Interview (ADI) domain describing repetitive and stereotyped behaviors (P = 0.007). We conclude that TPH2 may play a modest role in autism susceptibility, perhaps relating specifically to repetitive behaviors, pending replication of this result.
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Affiliation(s)
- Hilary Coon
- Neurodevelopmental Genetics Project, Department of Psychiatry, University of Utah, Salt Lake City, Utah 84108, USA.
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Wu S, Guo Y, Jia M, Ruan Y, Shuang M, Liu J, Gong X, Zhang Y, Yang J, Yang X, Zhang D. Lack of evidence for association between the serotonin transporter gene (SLC6A4) polymorphisms and autism in the Chinese trios. Neurosci Lett 2005; 381:1-5. [PMID: 15882779 DOI: 10.1016/j.neulet.2005.01.073] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 01/03/2005] [Accepted: 01/24/2005] [Indexed: 11/24/2022]
Abstract
Serotonin regulates several aspects of brain development, and it is involved in a range of behaviors frequently disturbed in autistic disorder. The serotonin transporter is a critical component of the serotonergic system. The serotonin transporter gene (SLC6A4) is of special interest given the nature of the biological findings and the reported effects of selective serotonin reuptake inhibitors of autistic symptoms. So far the genetics researches of the SLC6A4 gene have given conflicting results. The aim of study was to investigate the association between the SLC6A4 gene and autism in the Chinese Han population. The present study was conducted with the detection of three single nucleotide polymorphisms (SNP(S)) located within the SLC6A4 gene by using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) analysis. We performed a family-based association study of these polymorphisms in 175 Chinese Han family trios. Linkage disequilibrium (LD) measurement (D') analysis showed the presence of LD between markers across the locus. No significant evidence of association was found at any of the markers detected by using the transmission disequilibrium test (TDT) and haplotype analyses in all samples and male samples. Our findings suggest that it is unlikely that DNA variations in the SLC6A4 gene play a significant role in the genetic predisposition to autism in the Chinese Han population or that allelic heterogeneity at the SLC6A4 loci dilutes potential disease-allele association.
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Affiliation(s)
- Suping Wu
- Department of Biochemistry, Institute of Mental Health, No. 51 Hua Yuan Bei Road, Peking University, 100083 Beijing, China
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Chugani DC. Neuroepileptic correlates of autistic symptomatology in tuberous sclerosis. ACTA ACUST UNITED AC 2005; 10:112-6. [PMID: 15362166 DOI: 10.1002/mrdd.20021] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tuberous sclerosis is a genetic condition that is strongly associated with the development of an autism spectrum disorder. However, there is marked variability in expression, and only a subset of children with tuberous sclerosis develop autism spectrum disorder. Clarification of the mechanisms that underlie the association and variability in expression will potentially throw light on the biological processes involved in the etiology of idiopathic forms of autism spectrum disorder. Current evidence indicates that the likelihood of a child with tuberous sclerosis developing an autism spectrum disorder is greater if the child has a mutation in the TSC2 gene, although autism can and does develop in children with TSC1 mutations. The likelihood is also greater if the child has early-onset infantile spasms that are difficult to control, especially if there is an epileptiform focus in the temporal lobes. The emerging evidence is consistent with the notion that early onset electrophysiological disturbances within the temporal lobes (and perhaps other locations) has a deleterious effect on the development and establishment of key social cognitive representations concerned with processing social information, perhaps especially from faces. However, alternative mechanisms to account for the findings cannot yet be ruled out. Future research will have to employ prospective longitudinal designs and treatment trials to clarify the processes involved.
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Affiliation(s)
- Diane C Chugani
- Departments of Pediatrics and Radiology, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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Welch MG, Ruggiero DA. Predicted role of secretin and oxytocin in the treatment of behavioral and developmental disorders: implications for autism. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 71:273-315. [PMID: 16512355 DOI: 10.1016/s0074-7742(05)71012-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Martha G Welch
- Department of Psychiatry, Division of Neuroscience, Columbia University College of Physicians & Surgeons, New York, New York 10032, USA
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Bartlett CW, Gharani N, Millonig JH, Brzustowicz LM. Three autism candidate genes: a synthesis of human genetic analysis with other disciplines. Int J Dev Neurosci 2004; 23:221-34. [PMID: 15749247 DOI: 10.1016/j.ijdevneu.2004.10.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Revised: 10/20/2004] [Accepted: 10/21/2004] [Indexed: 11/26/2022] Open
Abstract
Autism is a particularly complex disorder when considered from virtually any methodological framework, including the perspective of human genetics. We first present a review of the genetic analysis principles relevant for discussing autism genetics research. From this body of work we highlight results from three candidate genes, REELIN (RELN), SEROTONIN TRANSPORTER (5HTT), and ENGRAILED 2 (EN2) and discuss the relevant neuroscience, molecular genetics, and statistical results that suggest involvement of these genes in autism susceptibility. As will be shown, the statistical results from genetic analysis, when considered alone, are in apparent conflict across research groups. We use these three candidate genes to illustrate different problems in synthesizing results from non-overlapping research groups examining the same problem. However, when basic genetic principles and results from other scientific disciplines are incorporated into a unified theoretical framework, at least some of the difficulties with interpreting results can be understood and potentially overcome as more data becomes available to the field of autism research. Integrating results from several scientific frameworks provides new hypotheses and alternative data collection strategies for future work.
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Whitaker-Azmitia PM. Behavioral and cellular consequences of increasing serotonergic activity during brain development: a role in autism? Int J Dev Neurosci 2004; 23:75-83. [PMID: 15730889 DOI: 10.1016/j.ijdevneu.2004.07.022] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Accepted: 07/30/2004] [Indexed: 11/22/2022] Open
Abstract
The hypothesis explored in this review is that the high levels of serotonin in the blood seen in some autistic children (the so-called hyperserotonemia of autism) may lead to some of the behavioral and cellular changes also observed in the disorder. At early stages of development, when the blood-brain Barrier is not yet fully formed, the high levels of serotonin in the blood can enter the brain of a developing fetus and cause loss of serotonin terminals through a known negative feedback function of serotonin during development. The loss of serotonin innervation persists throughout subsequent development and the symptoms of autism appear. A review of the basic scientific literature on prenatal treatments affecting serotonin is given, in support of this hypothesis, with an emphasis on studies using the serotonin agonist, 5-methoxytryptamine (5-MT). In work using 5-MT to mimic hyperserotonemia, Sprague-Dawley rats are treated from gestational day 12 until postnatal 20. In published reports, these animals have been found to have a significant loss of serotonin terminals, decreased metabolic activity in cortex, changes in columnar development in cortex, changes in serotonin receptors, and "autistic-like" behaviors. In preliminary cellular findings given in this review, the animals have also been found to have cellular changes in two relevant brain regions: 1. Central nucleus of the amygdala, a brain region involved in fear-responding, where an increase in calcitonin gene related peptide (CGRP) was found 2. Paraventricular nucleus of the hypothalamus, a brain region involved in social memory and bonding, where a decrease in oxytocin was found. Both of these cellular changes could result from loss of serotonin innervation, possibly due to loss of terminal outgrowth from the same cells of the raphe nuclei. Thus, increased serotonergic activity during development could damage neurocircuitry involved in emotional responding to social stressors and may have relevance to the symptoms of autism.
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Mulder EJ, Anderson GM, Kema IP, de Bildt A, van Lang NDJ, den Boer JA, Minderaa RB. Platelet serotonin levels in pervasive developmental disorders and mental retardation: diagnostic group differences, within-group distribution, and behavioral correlates. J Am Acad Child Adolesc Psychiatry 2004; 43:491-9. [PMID: 15187810 DOI: 10.1097/00004583-200404000-00016] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate group differences, the within-group distributions, and the clinical correlates of platelet serotonin (5-HT) levels in pervasive developmental disorders (PDD). METHOD Platelet 5-HT levels were measured in Dutch children and young adults, recruited from 2001 through 2003, with PDD (autism, Asperger's, and PDD-not otherwise specified [PDD-NOS]; n = 81) or with mental retardation (MR; n = 54) but without PDD, and in normal controls (n = 60). The distribution of platelet 5-HT levels was assessed using mixture-modeling analyses. Relationships between platelet 5-HT levels and a full range of demographic, clinical, and behavioral variables were examined. RESULTS Group mean (+/- SD) platelet 5-HT levels (nmol/10 platelets) were significantly higher in the autistic (4.51 +/- 1.61, n = 33) and PDD-NOS (4.90 +/- 1.54, n = 43) groups compared to the MR (3.48 +/- 1.33, n = 54) or the normal control (3.58 +/- 1.08, n = 60) groups (F4,190 = 9.35, p <.001). Platelet 5-HT values in the combined PDD group showed a bimodal distribution, and an empirical cutpoint for hyperserotonemia was determined. None of the behavioral variables examined was significantly associated with platelet 5-HT levels. CONCLUSIONS The platelet hyperserotonemia of autism was replicated in Dutch subjects. Platelet 5-HT levels were also increased in PDD-NOS, while no elevation was seen in MR. Platelet 5-HT levels appeared to be bimodally distributed in the PDD group, with an apparent hyperserotonemic subgroup.
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Affiliation(s)
- Erik J Mulder
- Child and Adolescent Psychiatry Center, University of Groningen, The Netherlands.
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Jones MB, Palmour RM, Zwaigenbaum L, Szatmari P. Modifier effects in autism at the MAO-A and DBH loci. Am J Med Genet B Neuropsychiatr Genet 2004; 126B:58-65. [PMID: 15048649 DOI: 10.1002/ajmg.b.20172] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Autism is one of a group of pervasive developmental disorders (PDD) characterized by qualitative impairments in reciprocal social communication and by a preference for repetitive, stereotyped activities, interests, and behaviors. The disorder is caused in large part by genetic mechanisms, though no disease genes have yet been identified. The objective of this study was to investigate three markers, two in the DBH gene and one in the MAO-A gene, for maternal or fetal modifier effects on level of functioning (IQ). At the same time, the possibility of maternal or fetal susceptibility effects was also examined. We assembled 67 affected sibpairs and 45 singletons and determined allele frequencies at the three markers among the affected children and first degree relatives. Sizeable and significant modifier effects were found at the MAO locus and, to a lesser extent, at the DBH locus. Susceptibility effects were also found but not without qualification. We conclude that maternal genotypes at the MAO-A locus, and possibly at the DBH one, may modify IQ in children with autism through the intrauterine environment.
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Affiliation(s)
- Marshall B Jones
- Department of Behavioral Science, The Pennsylvania State University College of Medicine, Hershey, PA, USA
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Coutinho AM, Oliveira G, Morgadinho T, Fesel C, Macedo TR, Bento C, Marques C, Ataíde A, Miguel T, Borges L, Vicente AM. Variants of the serotonin transporter gene (SLC6A4) significantly contribute to hyperserotonemia in autism. Mol Psychiatry 2004; 9:264-71. [PMID: 15094787 DOI: 10.1038/sj.mp.4001409] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The role of the serotonin system in the etiology and pathogenesis of autism spectrum disorders (ASD) is not clearly defined. High levels of platelet serotonin (5-HT) have been consistently found in a proportion of patients, and it is known that specific 5-HT transporter gene (SLC6A4) variants modulate transporter reuptake function, therefore possibly influencing the occurrence of hyperserotonemia in a subset of autistic patients. We have examined the association of platelet serotonin levels with two SLC6A4 polymorphisms, 5-HTT gene-linked polymorphic region (HTTLPR) in the promoter and intron 2 variable number of tandem repeats (VNTR), in a sample of 105 ASD patients, their parents, and 52 control children. Quantitative transmission disequilibrium test (QTDT) results showed a significant effect on 5-HT levels of each SLC6A4 marker (P=0.017 for HTTLPR; P=0.047 for intron 2 VNTR) and of haplotypes of the two markers (P=0.017), with a major contribution of the L.Stin2.10 haplotype (P=0.0013). A 5-HT mean value in the range of hyperserotonemia was associated with the homozygous L.Stin2.10 haplotype (H (1,N=97)=7.76, P=0.0054), which occurred in 33% of hyperserotonemic patients against 6% of patients with normal 5-HT levels (Fisher's exact test: P=0.013, OR=8). Allele interaction at the HTTLPR locus was found, with a significant dominance variance effect on 5-HT levels. We found no transmission disequilibrium of any of the SLC6A4 variants in ASD. Our results show that the SLC6A4 gene is a significant factor in the determination of 5-HT levels, and that specific SLC6A4 variants are associated with an increased risk for hyperserotonemia in our sample of autistic patients. The biological mechanism, however, is unlikely to involve the SLC6A4 gene solely. The associated SLC6A4 alleles likely interact with other genes or environmental factors to produce the abnormally high 5-HT levels observed in this subset of autistic patients, who possibly represent a separate etiological group.
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Affiliation(s)
- A M Coutinho
- Instituto Gulbenkian de Ciência, R Quinta Grande, 6, 2781-196 Oeiras, Portugal
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Nicolson R, Szatmari P. Genetic and neurodevelopmental influences in autistic disorder. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2003; 48:526-37. [PMID: 14574828 DOI: 10.1177/070674370304800804] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE In the past, autism was considered to be largely psychogenic. However, research in the last 2 decades indicates that autism is largely caused by genetic factors that lead to abnormal brain development. This article reviews research into the genetic and neurodevelopmental factors underlying autism. METHODS We review the findings from genetic and brain-imaging studies of autism over the past 15 years and synthesize these findings as a guide for future research. RESULTS Genome scans and association studies have suggested potential genomic regions and genes, respectively, that may be involved in the etiology of autism, and there have been some replications of these results. Similarly, the findings that brain volume is exaggerated in autism and corpus callosum size is reduced have also been independently replicated. Unfortunately, studies of other subcortical structures remain inconclusive or contradictory. CONCLUSIONS Overwhelming evidence now supports a neurobiological basis for autism. However, further refinements will be needed to guide future studies, particularly to identify the most informative phenotypes to investigate. Additionally, studies examining the role of genetic factors in the brain abnormalities underlying autism will likely lead to further findings that will enhance our understanding of autism's causes.
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Affiliation(s)
- Rob Nicolson
- Department of Psychiatry, University of Western Ontario, London, Ontario.
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Goussé V, Plumet MH, Chabane N, Mouren-Siméoni MC, Ferradian N, Leboyer M. Fringe phenotypes in autism: a review of clinical, biochemical and cognitive studies. Eur Psychiatry 2002; 17:120-8. [PMID: 12052572 DOI: 10.1016/s0924-9338(02)00640-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Progress in identifying the genetic vulnerability factors in autism requires correct identification of the inherited phenotype(s). This can be achieved not only by the accurate description of the affected subject but also by the identification of vulnerability traits in non-affected relatives of autistic probands. This review will focus on this last strategy and principally on clinical, biochemical and cognitive traits.
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Affiliation(s)
- Véronique Goussé
- Consultation autisme, service de psychopathologie de l'enfant et de l'adolescent, hôpital Robert Debré, assistance publique-hôpitaux de Paris, 75019, Paris, France
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Betancur C, Corbex M, Spielewoy C, Philippe A, Laplanche JL, Launay JM, Gillberg C, Mouren-Siméoni MC, Hamon M, Giros B, Nosten-Bertrand M, Leboyer M. Serotonin transporter gene polymorphisms and hyperserotonemia in autistic disorder. Mol Psychiatry 2002; 7:67-71. [PMID: 11803447 PMCID: PMC1896269 DOI: 10.1038/sj/mp/4000923] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2000] [Revised: 03/09/2001] [Accepted: 03/27/2001] [Indexed: 11/09/2022]
Abstract
Previous studies have provided conflicting evidence regarding the association of the serotonin transporter (5-HTT) gene with autism. Two polymorphisms have been identified in the human 5-HTT gene, a VNTR in intron 2 and a functional deletion/insertion in the promoter region (5-HTTLPR) with short and long variants. Positive associations of the 5-HTTLPR polymorphism with autism have been reported by two family-based studies, but one found preferential transmission of the short allele and the other of the long allele. Two subsequent studies failed to find evidence of transmission disequilibrium at the 5-HTTLPR locus. These conflicting results could be due to heterogeneity of clinical samples with regard to serotonin (5-HT) blood levels, which have been found to be elevated in some autistic subjects. Thus, we examined the association of the 5-HTTLPR and VNTR polymorphisms of the 5-HTT gene with autism, and we investigated the relationship between 5-HTT variants and whole-blood 5-HT. The transmission/disequilibrium test (TDT) revealed no linkage disequilibrium at either loci in a sample of 96 families comprising 43 trios and 53 sib pairs. Furthermore, no significant relationship between 5-HT blood levels and 5-HTT gene polymorphisms was found. Our results suggest that the 5-HTT gene is unlikely to play a major role as a susceptibility factor in autism.
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Affiliation(s)
- C Betancur
- INSERM U513, Faculté de Médecine, 94000 Créteil, France.
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Leboyer M, Philippe A, Bouvard M, Guilloud-Bataille M, Bondoux D, Tabuteau F, Feingold J, Mouren-Simeoni MC, Launay JM. Whole blood serotonin and plasma beta-endorphin in autistic probands and their first-degree relatives. Biol Psychiatry 1999; 45:158-63. [PMID: 9951562 DOI: 10.1016/s0006-3223(97)00532-5] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Whole blood serotonin (5-HT) and C-terminally directed beta-endorphin protein immunoreactivity (C-ter-beta-EP-ir) are known to be elevated in autistic subjects and might be possible markers of genetic liability to autism. This study thus investigates the familial aggregation of 5-HT and of C-ter-beta-EP-ir levels in first degree relatives of autistic probands. METHODS In a sample of 62 autistic subjects and 122 of their first-degree relatives, compared to age and sex-matched controls, we measured 5-HT by radioenzymology and C-ter-beta-EP-ir by radioimmunoassay. RESULTS We confirm the previously reported familiality of hyperserotoninemia in autism as mothers (51%), fathers (45%) and siblings (87%) have elevated levels of 5-HT, and we reveal presence of elevated levels of C-ter-beta-EP-ir in mothers (53%) of autistic subjects. CONCLUSIONS Familial aggregation of quantitative variables, such as concentration of neurotransmitters, within unaffected relative could serve as an intermediate phenotype and might thus help the search of genetic susceptibility factors in autism.
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Affiliation(s)
- M Leboyer
- INSERM U155, Faculté Jussieu, Paris, France
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McBride PA, Anderson GM, Hertzig ME, Snow ME, Thompson SM, Khait VD, Shapiro T, Cohen DJ. Effects of diagnosis, race, and puberty on platelet serotonin levels in autism and mental retardation. J Am Acad Child Adolesc Psychiatry 1998; 37:767-76. [PMID: 9666633 DOI: 10.1097/00004583-199807000-00017] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To reevaluate platelet serotonin (5-HT) levels in autism, measuring and controlling for effects of race and puberty. The specificity of hyperserotonemia for autism versus cognitive impairment is also assessed. METHOD Platelet 5-HT levels were measured in 77 individuals, aged 2 through 37 years, with autistic disorder; 65 normal controls; and 22 mentally retarded or otherwise cognitively impaired (MR/CI) prepubertal children. Effects of diagnosis, race, and pubertal status were evaluated by analysis of variance in separate pre- and postpubertal groups. 5-HT levels were expressed as ng/mL blood and ng/microL platelet volume. RESULTS Among prepubertal children, significant effects of diagnosis (ng/mL; F2,109 = 5.9, p = .004) and race (F2,109 = 14.7, p < .0005) were found. Autistic youngsters had significantly higher 5-HT concentrations than controls, although the elevation (25%) was less than typically reported; MR/CI children had levels very similar to those of controls. White children had significantly lower 5-HT levels than black or Latino youngsters, regardless of diagnosis. Diagnosis and race effects were nonsignificant in the postpubertal group. Postpubertal subjects had lower 5-HT concentrations than prepubertal subjects (ng/mL; F1,114 = 28.5, p < .0005). CONCLUSIONS The data underscore the importance of matching for race and pubertal status in neuropsychiatric research and suggest that the prevalence of hyperserotonemia in autistic individuals may have been overestimated because of a failure to control for both variables. Hyperserotonemia was not found in MR/CI youngsters without autistic features.
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Affiliation(s)
- P A McBride
- Department of Psychiatry, Cornell University Medical College, New York, USA
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Boutin P, Maziade M, Mérette C, Mondor M, Bédard C, Thivierge J. Family history of cognitive disabilities in first-degree relatives of autistic and mentally retarded children. J Autism Dev Disord 1997; 27:165-76. [PMID: 9105967 DOI: 10.1023/a:1025891824269] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We compared with a family history method the rate of cognitive disabilities (CD) in 156 first-degree relatives of 49 autistic (AU) probands to that found in 55 first-degree relatives of 18 mentally retarded (MR) probands. Broadly defined CD were found in, respectively, 17 and 16% of the relatives of the AU and MR probands. However, the characteristics of the probands associated with a family history of CD are different in AU and MR: Female and low IQ AU probands have more first-degree relatives with CD. Our findings suggest that a positive family history of CD is not specific to autism when compared to mental retardation. The observation that female and low IQ probands have higher family history of CD may suggest heterogeneity within autistic children and provides leads for future family studies.
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Affiliation(s)
- P Boutin
- Centre de recherche Université Laval Robert-Giffard, Beauport (Québec), Canada
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