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Maletic V, Mattingly GW, Earnest J. Viloxazine extended-release capsules as an emerging treatment for attention-deficit/hyperactivity disorder in children and adolescents. Expert Rev Neurother 2024; 24:443-455. [PMID: 38502148 DOI: 10.1080/14737175.2024.2327533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 03/04/2024] [Indexed: 03/20/2024]
Abstract
INTRODUCTION Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention and/or hyperactivity and impulsivity. Viloxazine extended-release (ER) capsules (Qelbree®) is a US Food and Drug Administration-approved nonstimulant treatment option for children, adolescents, and adults with ADHD. AREAS COVERED This review manuscript summarizes the neurobiology of ADHD and currently available treatment options before discussing viloxazine pharmacology, efficacy, safety, and tolerability data from phase II and III trials in children and adolescents (6-17 years old). Viloxazine clinical efficacy has also been further demonstrated by post hoc analyses of pediatric clinical trial results. EXPERT OPINION Current stimulant and nonstimulant treatments for ADHD may be suboptimal given low response rates and that tolerability issues are frequently experienced. Preclinical and clinical evidence has implicated both the role of catecholamine and serotonin signaling in the pathophysiology of ADHD and the pharmacologic effect of viloxazine on these critical neurotransmitter systems. With a relatively rapid onset of action, sustained symptom improvement, and clinical benefit in ADHD-associated impairments (functional and social), viloxazine ER represents a novel and emerging ADHD treatment option.
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Affiliation(s)
- Vladimir Maletic
- Department of Psychiatry and Behavioral Science, University of South Carolina School of Medicine, Greenville, SC, USA
| | - Gregory W Mattingly
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Jami Earnest
- Medical Affairs, Supernus Pharmaceuticals, Inc, Rockville, MD, USA
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Trujillo V, Camilo TA, Valentim-Lima E, Carbalan QSR, Dos-Santos RC, Felintro V, Reis LC, Lustrino D, Rorato R, Mecawi AS. Neonatal treatment with para-chlorophenylalanine (pCPA) induces adolescent hyperactivity associated with changes in the paraventricular nucleus Crh and Trh expressions. Behav Brain Res 2024; 462:114867. [PMID: 38246394 DOI: 10.1016/j.bbr.2024.114867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 01/12/2024] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
Disruption of the brain serotoninergic (5-HT) system during development induces long-lasting changes in molecular profile, cytoarchitecture, and function of neurons, impacting behavioral regulation throughout life. In male and female rats, we investigate the effect of neonatal tryptophan hydroxylase (TPH) inhibition by using para-chlorophenylalanine (pCPA) on the expression of 5-HTergic system components and neuropeptides related to adolescent social play behavior regulation. We observed sex-dependent 5-HT levels decrease after pCPA-treatment in the dorsal raphe nucleus (DRN) at 17 and 35 days. Neonatal pCPA-treatment increased playing, social and locomotory behaviors assessed in adolescent rats of both sexes. The pCPA-treated rats demonstrated decreased Crh (17 days) and increased Trh (35 days) expression in the hypothalamic paraventricular nucleus (PVN). There was sex dimorphism in Htr2c (17 days) and VGF (35 days) in the prefrontal cortex, with the females expressing higher levels of it than males. Our results indicate that neonatal pCPA-treatment results in a long-lasting and sex-dependent DRN 5-HT synthesis changes, decreased Crh, and increased Trh expression in the PVN, resulting in a hyperactivity-like phenotype during adolescence. The present work demonstrates that the impairment of TPH function leads to neurobehavioral disorders related to hyperactivity and impulsivity, such as attention deficit hyperactivity disorder (ADHD).
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Affiliation(s)
- Verónica Trujillo
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil; Department of Physiology, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Tays Araújo Camilo
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Evandro Valentim-Lima
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Quézia S R Carbalan
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Brazil
| | - Raoni C Dos-Santos
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Brazil
| | - Viviane Felintro
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Brazil
| | - Luís C Reis
- Department of Physiological Sciences, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Brazil
| | - Danilo Lustrino
- Laboratory of Basic and Behavioral Neuroendocrinology, Department of Physiology, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Sergipe (UFS), São Cristóvão, Brazil
| | - Rodrigo Rorato
- Laboratory of Stress Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - André S Mecawi
- Laboratory of Molecular Neuroendocrinology, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
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Wilson SK, Thomas J. BH4 as a Therapeutic Target for ADHD: Relevance to Neurotransmitters and Stress-Driven Symptoms. J Atten Disord 2024; 28:161-167. [PMID: 37942650 DOI: 10.1177/10870547231204012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Tetrahydrobiopterin (BH4) is a critical cofactor in a variety of metabolic pathways that have been linked to ADHD. There have been no previous studies utilizing BH4 as a supplement for ADHD. BH4 has been approved as a treatment for phenylketonuria (PKU). Individuals with PKU and ADHD appear to have low DA levels in common, suggesting that the hypodopaminergic state seen in both illnesses could be a relationship between the two. Clinical research involving supplementation of BH4 has shown low occurrence of adverse. In experiments, BH4 has also been found to have good blood-brain barrier permeability. BH4 also has the ability in scavenging ROS activity, which is an implication of stress and is seen in ADHD. BH4's significance in ADHD is reviewed in this paper because of its involvement in numerous neurodevelopmental metabolic pathways, and we anticipate that exogenous BH4 can be used to treat ADHD.
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Affiliation(s)
- Samson K Wilson
- Department of Pharmacology, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Science Campus, Kochi, Kerala
| | - Jaya Thomas
- Department of Pharmacology, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham, AIMS Health Science Campus, Kochi, Kerala
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Kessi M, Duan H, Xiong J, Chen B, He F, Yang L, Ma Y, Bamgbade OA, Peng J, Yin F. Attention-deficit/hyperactive disorder updates. Front Mol Neurosci 2022; 15:925049. [PMID: 36211978 PMCID: PMC9532551 DOI: 10.3389/fnmol.2022.925049] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/26/2022] [Indexed: 11/15/2022] Open
Abstract
Background Attention-deficit/hyperactive disorder (ADHD) is a neurodevelopmental disorder that commonly occurs in children with a prevalence ranging from 3.4 to 7.2%. It profoundly affects academic achievement, well-being, and social interactions. As a result, this disorder is of high cost to both individuals and society. Despite the availability of knowledge regarding the mechanisms of ADHD, the pathogenesis is not clear, hence, the existence of many challenges especially in making correct early diagnosis and provision of accurate management. Objectives We aimed to review the pathogenic pathways of ADHD in children. The major focus was to provide an update on the reported etiologies in humans, animal models, modulators, therapies, mechanisms, epigenetic changes, and the interaction between genetic and environmental factors. Methods References for this review were identified through a systematic search in PubMed by using special keywords for all years until January 2022. Results Several genes have been reported to associate with ADHD: DRD1, DRD2, DRD4, DAT1, TPH2, HTR1A, HTR1B, SLC6A4, HTR2A, DBH, NET1, ADRA2A, ADRA2C, CHRNA4, CHRNA7, GAD1, GRM1, GRM5, GRM7, GRM8, TARBP1, ADGRL3, FGF1, MAOA, BDNF, SNAP25, STX1A, ATXN7, and SORCS2. Some of these genes have evidence both from human beings and animal models, while others have evidence in either humans or animal models only. Notably, most of these animal models are knockout and do not generate the genetic alteration of the patients. Besides, some of the gene polymorphisms reported differ according to the ethnic groups. The majority of the available animal models are related to the dopaminergic pathway. Epigenetic changes including SUMOylation, methylation, and acetylation have been reported in genes related to the dopaminergic pathway. Conclusion The dopaminergic pathway remains to be crucial in the pathogenesis of ADHD. It can be affected by environmental factors and other pathways. Nevertheless, it is still unclear how environmental factors relate to all neurotransmitter pathways; thus, more studies are needed. Although several genes have been related to ADHD, there are few animal model studies on the majority of the genes, and they do not generate the genetic alteration of the patients. More animal models and epigenetic studies are required.
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Affiliation(s)
- Miriam Kessi
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Haolin Duan
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Baiyu Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Lifen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Yanli Ma
- Department of Neurology, Children’s Hospital Affiliated to Zhengzhou University, Henan Children’s Hospital, Zhengzhou Children’s Hospital, Zhengzhou, China
| | - Olumuyiwa A. Bamgbade
- Department of Anesthesiology and Pharmacology, University of British Columbia, Vancouver, BC, Canada
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- *Correspondence: Fei Yin,
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Chu CH, Chen JS, Chuang PC, Su CH, Chan YL, Yang YJ, Chiang YT, Su YY, Gean PW, Sun HS. TIAM2S as a novel regulator for serotonin level enhances brain plasticity and locomotion behavior. FASEB J 2020; 34:3267-3288. [PMID: 31908036 DOI: 10.1096/fj.201901323r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 10/18/2019] [Accepted: 12/23/2019] [Indexed: 11/11/2022]
Abstract
TIAM2S, the short form of human T-cell lymphoma invasion and metastasis 2, can have oncogenic effects when aberrantly expressed in the liver or lungs. However, it is also abundant in healthy, non-neoplastic brain tissue, in which its primary function is still unknown. Here, we examined the neurobiological and behavioral significance of human TIAM2S using the human brain protein panels, a human NT2/D1-derived neuronal cell line model (NT2/N), and transgenic mice that overexpress human TIAM2S (TIAM2S-TG). Our data reveal that TIAM2S exists primarily in neurons of the restricted brain areas around the limbic system and in well-differentiated NT2/N cells. Functional studies revealed that TIAM2S has no guanine nucleotide exchange factor (GEF) activity and is mainly located in the nucleus. Furthermore, whole-transcriptome and enrichment analysis with total RNA sequencing revealed that TIAM2S-knockdown (TIAM2S-KD) was strongly associated with the cellular processes of the brain structural development and differentiation, serotonin-related signaling, and the diseases markers representing neurobehavioral developmental disorders. Moreover, TIAM2S-KD cells display decreased neurite outgrowth and reduced serotonin levels. Moreover, TIAM2S overexpressing TG mice show increased number and length of serotonergic fibers at early postnatal stage, results in higher serotonin levels at both the serum and brain regions, and higher neuroplasticity and hyperlocomotion in latter adulthood. Taken together, our results illustrate the non-oncogenic functions of human TIAM2S and demonstrate that TIAM2S is a novel regulator of serotonin level, brain neuroplasticity, and locomotion behavior.
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Affiliation(s)
- Chun-Hsien Chu
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jia-Shing Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Chin Chuang
- Department of Medical Research, Chang Gung Memorial Hospital, Kaohsiung, Taiwan.,Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chia-Hao Su
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Ya-Ling Chan
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Ying-Ju Yang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ting Chiang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ya Su
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Po-Wu Gean
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.,Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - H Sunny Sun
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Dunn GA, Nigg JT, Sullivan EL. Neuroinflammation as a risk factor for attention deficit hyperactivity disorder. Pharmacol Biochem Behav 2019; 182:22-34. [PMID: 31103523 PMCID: PMC6855401 DOI: 10.1016/j.pbb.2019.05.005] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 05/08/2019] [Accepted: 05/14/2019] [Indexed: 01/08/2023]
Abstract
Attention Deficit Hyperactivity Disorder (ADHD) is a persistent, and impairing pediatric-onset neurodevelopmental condition. Its high prevalence, and recurrent controversy over its widespread identification and treatment, drive strong interest in its etiology and mechanisms. Emerging evidence for a role for neuroinflammation in ADHD pathophysiology is of great interest. This evidence includes 1) the above-chance comorbidity of ADHD with inflammatory and autoimmune disorders, 2) initial studies indicating an association with ADHD and increased serum cytokines, 3) preliminary evidence from genetic studies demonstrating associations between polymorphisms in genes associated with inflammatory pathways and ADHD, 4) emerging evidence that early life exposure to environmental factors may increase risk for ADHD via an inflammatory mechanism, and 5) mechanistic evidence from animal models of maternal immune activation documenting behavioral and neural outcomes consistent with ADHD. Prenatal exposure to inflammation is associated with changes in offspring brain development including reductions in cortical gray matter volume and the volume of certain cortical areas -parallel to observations associated with ADHD. Alterations in neurotransmitter systems, including the dopaminergic, serotonergic and glutamatergic systems, are observed in ADHD populations. Animal models provide strong evidence that development and function of these neurotransmitters systems are sensitive to exposure to in utero inflammation. In summary, accumulating evidence from human studies and animal models, while still incomplete, support a potential role for neuroinflammation in the pathophysiology of ADHD. Confirmation of this association and the underlying mechanisms have become valuable targets for research. If confirmed, such a picture may be important in opening new intervention routes.
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Affiliation(s)
| | - Joel T Nigg
- Oregon Health and Science University, United States of America
| | - Elinor L Sullivan
- University of Oregon, United States of America; Oregon Health and Science University, United States of America; Oregon National Primate Research Center, United States of America.
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Hou YW, Xiong P, Gu X, Huang X, Wang M, Wu J. Association of Serotonin Receptors with Attention Deficit Hyperactivity Disorder: A Systematic Review and Meta-analysis. Curr Med Sci 2018; 38:538-551. [DOI: 10.1007/s11596-018-1912-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/30/2017] [Indexed: 12/21/2022]
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Gomes CKF, Vieira-Fonseca T, Melo-Felippe FB, de Salles Andrade JB, Fontenelle LF, Kohlrausch FB. Association analysis of SLC6A4 and HTR2A genes with obsessive-compulsive disorder: Influence of the STin2 polymorphism. Compr Psychiatry 2018; 82:1-6. [PMID: 29331882 DOI: 10.1016/j.comppsych.2017.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/13/2017] [Accepted: 12/13/2017] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Obsessive-Compulsive Disorder (OCD) is a complex and chronic disorder characterized by recurrent thoughts and/or repetitive behaviors. Given the potent anti-obsessional effects of the so-called serotonin reuptake inhibitors, genes related to serotonergic system may be well implicated in the etiopathogenesis of OCD. The gene encoding the serotonin transporter (SLC6A4), which shows a variable number of tandem repeat (VNTR) polymorphism in intron 2 (STin2), have been previously associated with OCD. Additionally, the serotonin 2A receptor gene (HTR2A) has two polymorphisms (A-1438G - rs6311, and T102C - rs6313), which have also been overrepresented among OCD patients. Therefore, the aim of this study is to evaluate the association of these three polymorphisms with OCD, through the examination of potential sources of heterogeneity in previous studies including age of onset, sex and symptom dimensions. METHODS Polymorphisms were genotyped by Polymerase Chain Reaction (PCR) in a sample of 203 OCD patients and 205 healthy controls from Brazil. RESULTS Although we did not observe any statistically significant association between the HTR2A gene polymorphisms and OCD or its clinical features, SLC6A4 STin2 polymorphism was significantly more common among OCD patients as compared to health controls. Further, a significant association between the STin2.12 allele and OCD, as well as a dominant effect of the STin2.12 allele in OCD was seen. Of note, late-onset (>18years) OCD was significantly more often seen in association with homozygosis for STin2.12 allele. No significant associations were observed with different OCD symptom dimensions. CONCLUSION Our results indicate an important influence of the STin2 polymorphism in OCD, but more studies are warranted to confirm these results.
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Affiliation(s)
| | - Tamiris Vieira-Fonseca
- Departamento de Biologia Geral, Instituto de Biologia, Universidade Federal Fluminense (UFF), Niterói, Brazil
| | - Fernanda Brito Melo-Felippe
- Departamento de Biologia Geral, Instituto de Biologia, Universidade Federal Fluminense (UFF), Niterói, Brazil
| | - Juliana Braga de Salles Andrade
- Programa de Transtornos Obsessivo-Compulsivos e de Ansiedade, Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Leonardo F Fontenelle
- Programa de Transtornos Obsessivo-Compulsivos e de Ansiedade, Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; Instituto D'Or de Pesquisa e Ensino (IDOR), Rio de Janeiro, Brazil; School of Psychological Sciences, MONASH University, Melbourne, Australia
| | - Fabiana Barzotti Kohlrausch
- Departamento de Biologia Geral, Instituto de Biologia, Universidade Federal Fluminense (UFF), Niterói, Brazil.
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Klein M, Onnink M, van Donkelaar M, Wolfers T, Harich B, Shi Y, Dammers J, Arias-Vásquez A, Hoogman M, Franke B. Brain imaging genetics in ADHD and beyond - Mapping pathways from gene to disorder at different levels of complexity. Neurosci Biobehav Rev 2017; 80:115-155. [PMID: 28159610 PMCID: PMC6947924 DOI: 10.1016/j.neubiorev.2017.01.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/08/2016] [Accepted: 01/09/2017] [Indexed: 01/03/2023]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a common and often persistent neurodevelopmental disorder. Beyond gene-finding, neurobiological parameters, such as brain structure, connectivity, and function, have been used to link genetic variation to ADHD symptomatology. We performed a systematic review of brain imaging genetics studies involving 62 ADHD candidate genes in childhood and adult ADHD cohorts. Fifty-one eligible research articles described studies of 13 ADHD candidate genes. Almost exclusively, single genetic variants were studied, mostly focussing on dopamine-related genes. While promising results have been reported, imaging genetics studies are thus far hampered by methodological differences in study design and analysis methodology, as well as limited sample sizes. Beyond reviewing imaging genetics studies, we also discuss the need for complementary approaches at multiple levels of biological complexity and emphasize the importance of combining and integrating findings across levels for a better understanding of biological pathways from gene to disease. These may include multi-modal imaging genetics studies, bioinformatic analyses, and functional analyses of cell and animal models.
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Affiliation(s)
- Marieke Klein
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Marten Onnink
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Marjolein van Donkelaar
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Thomas Wolfers
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Benjamin Harich
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Yan Shi
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Janneke Dammers
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Department of Psychiatry, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Alejandro Arias-Vásquez
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Department of Psychiatry, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Department of Cognitive Neuroscience, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Martine Hoogman
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Barbara Franke
- Department of Human Genetics, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Department of Psychiatry, Radboud university medical center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
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Systems Pharmacology Based Study of the Molecular Mechanism of SiNiSan Formula for Application in Nervous and Mental Diseases. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:9146378. [PMID: 28058059 PMCID: PMC5183803 DOI: 10.1155/2016/9146378] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/25/2016] [Accepted: 11/09/2016] [Indexed: 12/27/2022]
Abstract
Background. Mental disorder is a group of systemic diseases characterized by a variety of physical and mental discomfort, which has become the rising threat to human life. Herbal medicines were used to treat mental disorders for thousand years in China in which the molecular mechanism is not yet clear. Objective. To systematically explain the mechanisms of SiNiSan (SNS) formula on the treatment of mental disorders. Method. A systems pharmacology method, with ADME screening, targets prediction, and DAVID enrichment analysis, was employed as the principal approach in our study. Results. 60 active ingredients of SNS formula and 187 mental disorders related targets were discovered to have interactions with them. Furthermore, the enrichment analysis of drug-target network showed that SNS probably acts through “multi-ingredient, multitarget, and multisystems” holistic coordination in different organs pattern by indirectly regulating the nutritional and metabolic pathway even their serial complications. Conclusions. Our research provides a reference for the molecular mechanism of medicinal herbs in the treatment of mental disease on a systematic level. Hopefully, it will also provide a theoretical basis for the discovery of lead compounds of natural medicines for other diseases based on traditional medicine.
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Aznar S, Hervig MES. The 5-HT2A serotonin receptor in executive function: Implications for neuropsychiatric and neurodegenerative diseases. Neurosci Biobehav Rev 2016; 64:63-82. [DOI: 10.1016/j.neubiorev.2016.02.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 11/05/2015] [Accepted: 02/08/2016] [Indexed: 02/07/2023]
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Fluegge KR, Fluegge KR. Glyphosate Use Predicts ADHD Hospital Discharges in the Healthcare Cost and Utilization Project Net (HCUPnet): A Two-Way Fixed-Effects Analysis. PLoS One 2015; 10:e0133525. [PMID: 26287729 PMCID: PMC4543553 DOI: 10.1371/journal.pone.0133525] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 06/29/2015] [Indexed: 11/19/2022] Open
Abstract
There has been considerable international study on the etiology of rising mental disorders, such as attention-deficit hyperactivity disorder (ADHD), in human populations. As glyphosate is the most commonly used herbicide in the world, we sought to test the hypothesis that glyphosate use in agriculture may be a contributing environmental factor to the rise of ADHD in human populations. State estimates for glyphosate use and nitrogen fertilizer use were obtained from the U.S. Geological Survey (USGS). We queried the Healthcare Cost and Utilization Project net (HCUPNET) for state-level hospitalization discharge data in all patients for all-listed ADHD from 2007 to 2010. We used rural-urban continuum codes from the USDA-Economic Research Service when exploring the effect of urbanization on the relationship between herbicide use and ADHD. Least squares dummy variable (LSDV) method and within method using two-way fixed effects was used to elucidate the relationship between glyphosate use and all-listed ADHD hospital discharges. We show that a one kilogram increase in glyphosate use, in particular, in one year significantly positively predicts state-level all-listed ADHD discharges, expressed as a percent of total mental disorders, the following year (coefficient = 5.54E-08, p<.01). A study on the effect of urbanization on the relationship between glyphosate and ADHD indicates that the relationship is marginally significantly positive after multiple comparison correction only in urban U.S. counties (p<.025). Furthermore, total glyphosate use is strongly positively associated with total farm use of nitrogen fertilizers from 1992 to 2006 (p<.001). We present evidence from the biomedical research literature of a plausible link among glyphosate, nitrogen dysbiosis and ADHD. Glyphosate use is a significant predictor of state hospitalizations for all-listed ADHD hospital discharges, with the effect concentrated in urban U.S. counties. This effect is seen even after controlling for individual state characteristics, strong correlations over time, and other significant associations with ADHD in the literature. We draw upon the econometric results to propose unique mechanisms, borrowing principles from soil and atmospheric sciences, for how glyphosate-based herbicides may be contributing to the rise of ADHD in all populations.
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Affiliation(s)
- Keith R. Fluegge
- Institute of Health and Environmental Research (IHER), Cleveland, Ohio, 44118 United States of America
- Graduate School, The Ohio State University, Columbus, Ohio, 43210, United States of America
| | - Kyle R. Fluegge
- Institute of Health and Environmental Research (IHER), Cleveland, Ohio, 44118 United States of America
- Department of Epidemiology & Biostatistics, Case Western Reserve University School of Medicine, Cleveland, Ohio, 44106, United States of America
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13
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Does serotonin deficit mediate susceptibility to ADHD? Neurochem Int 2015; 82:52-68. [DOI: 10.1016/j.neuint.2015.02.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/18/2015] [Accepted: 02/07/2015] [Indexed: 11/21/2022]
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14
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Barclay Z, Dickson L, Robertson D, Johnson M, Holland P, Rosie R, Sun L, Jerina H, Lutz E, Fleetwood-Walker S, Mitchell R. Attenuated PLD1 association and signalling at the H452Y polymorphic form of the 5-HT2A receptor. Cell Signal 2013; 25:814-21. [DOI: 10.1016/j.cellsig.2013.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 12/18/2012] [Accepted: 01/06/2013] [Indexed: 11/24/2022]
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15
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Ouchi H, Ono K, Murakami Y, Matsumoto K. Social isolation induces deficit of latent learning performance in mice: a putative animal model of attention deficit/hyperactivity disorder. Behav Brain Res 2012; 238:146-53. [PMID: 23103401 DOI: 10.1016/j.bbr.2012.10.029] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 09/24/2012] [Accepted: 10/17/2012] [Indexed: 01/06/2023]
Abstract
Social isolation of rodents (SI) elicits a variety of stress responses such as increased aggressiveness, hyper-locomotion, and reduced susceptibility to pentobarbital. To obtain a better understanding of the relevance of SI-induced behavioral abnormalities to psychiatric disorders, we examined the effect of SI on latent learning as an index of spatial attention, and discussed the availability of SI as an epigenetic model of attention deficit hyperactivity disorder (ADHD). Except in specially stated cases, 4-week-old male mice were housed in a group or socially isolated for 3-70 days before experiments. The animals socially isolated for 1 week or more exhibited spatial attention deficit in the water-finding test. Re-socialized rearing for 5 weeks after 1-week SI failed to attenuate the spatial attention deficit. The effect of SI on spatial attention showed no gender difference or correlation with increased aggressive behavior. Moreover, SI had no effect on cognitive performance elucidated in a modified Y-maze or an object recognition test, but it significantly impaired contextual and conditional fear memory elucidated in the fear-conditioning test. Drugs used for ADHD therapy, methylphenidate (1-10 mg/kg, i.p.) and caffeine (0.5-1 mg/kg, i.p.), improved SI-induced latent learning deficit in a manner reversible with cholinergic but not dopaminergic antagonists. Considering the behavioral features of SI mice together with their susceptibility to ADHD drugs, the present findings suggest that SI provides an epigenetic animal model of ADHD and that central cholinergic systems play a role in the effect of methylphenidate on SI-induced spatial attention deficit.
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Affiliation(s)
- Hirofumi Ouchi
- Division of Medicinal Pharmacology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
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Caylak E. Biochemical and genetic analyses of childhood attention deficit/hyperactivity disorder. Am J Med Genet B Neuropsychiatr Genet 2012; 159B:613-27. [PMID: 22825876 DOI: 10.1002/ajmg.b.32077] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Accepted: 06/26/2012] [Indexed: 02/05/2023]
Abstract
Attention deficit/hyperactivity disorder (ADHD) in children is a neurobehavioral disorder characterized by inattention, hyperactivity, and/or impulsivity. The biochemical abnormalities and genetic factors play significant roles in the etiology of ADHD. These symptoms affect the behavior performance and social relationships of children in school and at home. Recently, many studies about biochemical abnormalities in ADHD have been published. Several research groups have also suggested the genetic contribution to ADHD, and attempted to identify susceptibility and candidate genes for this disorder through the genetic linkage and association studies. To date, these studies have reported substantial evidence implicating several genes (dopaminergic: DRD4, DAT1, DRD5, COMT; noradrenergic: DBH, ADRA2A; serotonergic: 5-HTT, HTR1B, HTR2A; cholinergic: CHRNA4, and central nervous system development pathway: SNAP25, BDNF) in the etiology of ADHD. Understanding the biochemistry and genetics of ADHD will allow us to provide a useful addition with other treatment procedures for ADHD.
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Affiliation(s)
- Emrah Caylak
- Department of Biochemistry, School of Health, Karatekin University, Cankiri, Turkey.
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17
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Cho SC, Son JW, Kim BN, Kim JW, Yoo HJ, Hwang JW, Cho DY, Chung US, Park TW. Serotonin 2A Receptor Gene Polymorphism in Korean Children with Attention-Deficit/Hyperactivity Disorder. Psychiatry Investig 2012; 9:269-77. [PMID: 22993527 PMCID: PMC3440477 DOI: 10.4306/pi.2012.9.3.269] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/18/2012] [Accepted: 04/25/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The purpose of this study was to investigate the association between the T102C polymorphism in the serotonin 2A receptor gene and attention-deficit/hyperactivity disorder (ADHD) in Korean patients. METHODS A total of 189 Korean children with ADHD as well as both parents of the ADHD children and 150 normal children participated in this study. DNA was extracted from blood samples from all of the subjects, and genotyping was conducted. Based on the allele and genotype information obtained, case-control analyses were performed to compare the ADHD and normal children, and Transmission disequilibrium tests (TDTs) were used for family-based association testing (number of trios=113). Finally, according to the significant finding which was showed in the case-control analyses, the results of behavioral characterastics and neuropsychological test were compared between ADHD children with and without the C allele. RESULTS In the case-control analyses, statistically significant differences were detected in the frequencies of genotypes containing the C allele (χ(2)=4.73, p=0.030). In the family-based association study, TDTs failed to detect linkage disequilibrium of the T102C polymorphism associated with ADHD children. In the ADHD children, both the mean reaction time and the standard deviation of the reaction time in the auditory continuous performance test were longer in the group with the C allele compared to the group without the C allele. CONCLUSION The results of this study suggest that there is a significant genetic association between the T102C polymorphism in the serotonin 2A receptor gene and ADHD in Korean children.
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Affiliation(s)
- Soo-Churl Cho
- Department of Child and Adolescent Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jung-Woo Son
- Department of Neuropsychiatry, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Boong-Nyun Kim
- Department of Child and Adolescent Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae-Won Kim
- Department of Child and Adolescent Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hee-Jeong Yoo
- Department of Psychiatry, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Jun-Won Hwang
- Department of Neuropsychiatry, Kangwon National University School of Medicine, Chuncheon, Republic of Korea
| | - Dae-Yeon Cho
- LabGenomics Clinical Research Institute, LabGenomics, Seoul, Republic of Korea
| | - Un-Sun Chung
- Department of Psychiatry, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Won Park
- Department of Neuropsychiatry, College of Medicine, Chonbuk National University, Jeonju, Republic of Korea
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Huot P, Fox SH, Brotchie JM. The serotonergic system in Parkinson's disease. Prog Neurobiol 2011; 95:163-212. [PMID: 21878363 DOI: 10.1016/j.pneurobio.2011.08.004] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/05/2011] [Accepted: 08/15/2011] [Indexed: 01/23/2023]
Abstract
Although the cardinal manifestations of Parkinson's disease (PD) are attributed to a decline in dopamine levels in the striatum, a breadth of non-motor features and treatment-related complications in which the serotonergic system plays a pivotal role are increasingly recognised. Serotonin (5-HT)-mediated neurotransmission is altered in PD and the roles of the different 5-HT receptor subtypes in disease manifestations have been investigated. The aims of this article are to summarise and discuss all published preclinical and clinical studies that have investigated the serotonergic system in PD and related animal models, in order to recapitulate the state of the current knowledge and to identify areas that need further research and understanding.
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Affiliation(s)
- Philippe Huot
- Toronto Western Research Institute, MCL 11-419, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
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Russell VA. Overview of animal models of attention deficit hyperactivity disorder (ADHD). ACTA ACUST UNITED AC 2011; Chapter 9:Unit9.35. [PMID: 21207367 DOI: 10.1002/0471142301.ns0935s54] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous, highly heritable, behavioral disorder that affects ∼5% to 10% of children worldwide. Although animal models cannot truly reflect human psychiatric disorders, they can provide insight into the disorder that cannot be obtained from human studies because of the limitations of available techniques. Genetic models include the spontaneously hypertensive rat (SHR), the Naples High Excitability (NHE) rat, poor performers in the 5-choice serial reaction time (5-CSRT) task, the dopamine transporter (DAT) knock-out mouse, the SNAP-25 deficient mutant coloboma mouse, mice expressing a human mutant thyroid hormone receptor, a nicotinic receptor knock-out mouse, and a tachykinin-1 (NK1) receptor knock-out mouse. Chemically induced models of ADHD include prenatal or early postnatal exposure to ethanol, nicotine, polychlorinated biphenyls, or 6-hydroxydopamine (6-OHDA). Environmentally induced models have also been suggested; these include neonatal anoxia and rat pups reared in social isolation. The major insight provided by animal models was the consistency of findings regarding the involvement of dopaminergic, noradrenergic, and sometimes also serotonergic systems, as well as more fundamental defects in neurotransmission.
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Affiliation(s)
- Vivienne Ann Russell
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
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20
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Abstract
Studies employing animal models of attention-deficit/hyperactivity disorder (ADHD) present clear inherent advantages over human studies. Animal models are invaluable tools for the study of underlying neurochemical, neuropathological and genetic alterations that cause ADHD, because they allow relatively fast, rigorous hypothesis testing and invasive manipulations as well as selective breeding. Moreover, especially for ADHD, animal models with good predictive validity would allow the assessment of potential new therapeutics. In this chapter, we describe and comment on the most frequently used animal models of ADHD that have been created by genetic, neurochemical and physical alterations in rodents. We then discuss that an emerging and promising direction of the field is the analysis of individual behavioural differences among a normal population of animals. Subjects presenting extreme characteristics related to ADHD can be studied, thereby avoiding some of the problems that are found in other models, such as functional recovery and unnecessary assumptions about aetiology. This approach is justified by the theoretical need to consider human ADHD as the extreme part of a spectrum of characteristics that are distributed normally in the general population, as opposed to the predominant view of ADHD as a separate pathological category.
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Affiliation(s)
- A Bari
- Department of Experimental Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK,
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van Beijsterveldt CEM, Middeldorp CM, Slof-Op't Landt MCT, Bartels M, Hottenga JJ, Suchiman HED, Slagboom PE, Boomsma DI. Influence of candidate genes on attention problems in children: a longitudinal study. Behav Genet 2010; 41:155-64. [PMID: 21049304 PMCID: PMC3029680 DOI: 10.1007/s10519-010-9406-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 10/07/2010] [Indexed: 12/01/2022]
Abstract
Attention problems form one of the core characteristics of Attention-Deficit Hyperactive Disorder (ADHD), a multifactorial neurodevelopmental disorder. From twin research it is clear that genes play a considerable role in the etiology and in the stability of ADHD in childhood. Association studies have focused on genes involved in the dopaminergic and serotoninergic systems, but with inconclusive results. This study investigated the effect of 26 Single Nucleotide Polymorphisms (SNPs) in genes encoding for serotonin receptors 2A (HTR2A), Catechol-O-Methyltransferase (COMT), Tryptophane Hydroxylase type 2 (TPH2), and Brain Derived Neurotrophic Factor (BDNF). Attention problems (AP) were assessed by parental report at ages 3, 7, 10, and 12 years in more than 16,000 twin pairs. There were 1148 genotyped children with AP data. We developed a longitudinal framework to test the genetic association effect. Based on all phenotypic data, a longitudinal model was formulated with one latent factor loading on all AP measures over time. The broad heritability for the AP latent factor was 82%, and the latent factor explained around 55% of the total phenotypic variance. The association of SNPs with AP was then modeled at the level of this factor. None of the SNPs showed a significant association with AP. The lowest p-value was found for the rs6265 SNP in the BDNF gene (p = 0.035). Overall, our results suggest no evidence for a role of these genes in childhood AP.
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Affiliation(s)
- Catherina E M van Beijsterveldt
- Department of Biological Psychology, VU University Amsterdam, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands.
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Shim SH, Hwangbo Y, Kwon YJ, Jeong HY, Lee BH, Hwang JA, Kim YK. A case-control association study of serotonin 1A receptor gene and tryptophan hydroxylase 2 gene in attention deficit hyperactivity disorder. Prog Neuropsychopharmacol Biol Psychiatry 2010; 34:974-9. [PMID: 20470849 DOI: 10.1016/j.pnpbp.2010.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 05/04/2010] [Accepted: 05/05/2010] [Indexed: 01/26/2023]
Abstract
Serotonergic system-related genes are likely to be involved in mechanisms underlying attention deficit hyperactivity disorder (ADHD). We investigated the association of serotonin the 1A receptor C-1019G single nucleotide polymorphism (HTR1A C-1019G SNP) and tryptophan hydroxylase 2 gene -703G/T (TPH2 -703G/T) SNP with ADHD. All of the ADHD subjects completed a comprehensive and standardized diagnostic and psychological evaluation battery including the parents' Korean version of the ADHD Rating Scale-IV (ARS). The genotype and allele frequencies of 78 ADHD patients and 107 normal controls were analyzed for 5-HTR1A C-1019G and TPH2 -703G/T. There were statistically significant differences in the genotype distributions and allele frequencies of HTR1A C-1019G between the ADHD group and the control group. The homozygous allele C frequency was significantly higher in ADHD patients than in controls. However, no differences in either genotype distribution or in allele frequencies of TPH2 -703G/T were observed between the ADHD patients and the controls. In the ADHD patients, ANCOVA revealed that there were no significant differences in the subscales and total score between the ADHD probands with the CC genotype and those with the CG and GG genotypes in ARS and the Continuous Performance Test (CPT) when adjusting for age and gender. The odds ratio comparing the CC genotype group with the CG genotype group and the C allele with G was 2.12 and 1.79 respectively. Therefore, genotype CC was associated with higher risk of ADHD. Our results suggest that the HTR1A C-1019G SNP may affect susceptibility to ADHD. Further investigation with a larger number of subjects is needed in order to confirm this finding.
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Affiliation(s)
- Se-Hoon Shim
- Division of Child & Adolescent Psychiatry, Department of Psychiatry, Soonchunhyang University Cheonan Hospital, Cheonan City, Bongmyoung Dong 23-20 Choongnam Province, 330-721, South Korea
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Correlation of a set of gene variants, life events and personality features on adult ADHD severity. J Psychiatr Res 2010; 44:598-604. [PMID: 20006992 DOI: 10.1016/j.jpsychires.2009.11.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 11/12/2009] [Accepted: 11/13/2009] [Indexed: 11/21/2022]
Abstract
Increasing evidence suggests that symptoms of attention deficit hyperactivity disorder (ADHD) could persist into adult life in a substantial proportion of cases. The aim of the present study was to investigate the impact of (1) adverse events, (2) personality traits and (3) genetic variants chosen on the basis of previous findings and (4) their possible interactions on adult ADHD severity. One hundred and ten individuals diagnosed with adult ADHD were evaluated for occurrence of adverse events in childhood and adulthood, and personality traits by the Temperament and Character Inventory (TCI). Common polymorphisms within a set of nine important candidate genes (SLC6A3, DBH, DRD4, DRD5, HTR2A, CHRNA7, BDNF, PRKG1 and TAAR9) were genotyped for each subject. Life events, personality traits and genetic variations were analyzed in relationship to severity of current symptoms, according to the Brown Attention Deficit Disorder Scale (BADDS). Genetic variations were not significantly associated with severity of ADHD symptoms. Life stressors displayed only a minor effect as compared to personality traits. Indeed, symptoms' severity was significantly correlated with the temperamental trait of Harm avoidance and the character trait of Self directedness. The results of the present work are in line with previous evidence of a significant correlation between some personality traits and adult ADHD. However, several limitations such as the small sample size and the exclusion of patients with other severe comorbid psychiatric disorders could have influenced the significance of present findings.
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Abstract
Although twin studies demonstrate that ADHD is a highly heritable condition, molecular genetic studies suggest that the genetic architecture of ADHD is complex. The handful of genome-wide linkage and association scans that have been conducted thus far show divergent findings and are, therefore, not conclusive. Similarly, many of the candidate genes reviewed here (ie, DBH, MAOA, SLC6A2, TPH-2, SLC6A4, CHRNA4, GRIN2A) are theoretically compelling from neurobiological systems perspective but available data are sparse and inconsistent. However, candidate gene studies of ADHD have produced substantial evidence implicating several genes in the etiology of the disorder, with meta-analyses supportive of a role of the genes coding for DRD4, DRD5, SLC6A3, SNAP-25, and HTR1B in the etiology of ADHD.
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25
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Qiu J, Hong Q, Chen RH, Tong ML, Zhang M, Fei L, Pan XQ, Guo M, Guo XR, Chi X. Gene expression profiles in the prefrontal cortex of SHR rats by cDNA microarrays. Mol Biol Rep 2009; 37:1733-40. [PMID: 19572212 DOI: 10.1007/s11033-009-9596-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 06/18/2009] [Indexed: 10/20/2022]
Abstract
We have undertaken cDNA microarrays to identify differentially expressed genes in the prefrontal cortex (PFC) of spontaneously hypertensive-rat (SHR), a rodent model of attention deficit hyperactivity disorder (ADHD) versus control Wistar-Kyoto (WKY) rats. The analysis of the gene expression profiles indicated that 57 genes were up-regulated and 97 genes were down-regulated in the PFC of SHR. These predominately expressed genes included genes involved in neural development, immunity, transcription factor, monoamine neurotransmitter, metabolism, signal transduction, apoptosis and so on. Although more detailed analyses are necessary, it is anticipated that further study of genes identified will provide insights into their specific roles in the etiology of ADHD.
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Affiliation(s)
- Jie Qiu
- Department of Pediatrics, Nanjing Maternity and Child Health Hospital of Nanjing Medical University, 210004, Nanjing, China.
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Candidate gene analysis in an on-going genome-wide association study of attention-deficit hyperactivity disorder: suggestive association signals in ADRA1A. Psychiatr Genet 2009; 19:134-41. [PMID: 19352218 DOI: 10.1097/ypg.0b013e32832a5043] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVES Attention-deficit hyperactivity disorder (ADHD) is a highly heritable, common developmental disorder. Although a few confirmed associations have emerged from candidate gene studies, these have shown the same limitations that have become evident in the study of other complex diseases, often with inconsistent and nonreplicated results across different studies. METHODS In this report, 27 ADHD candidate genes were explored in greater depth using high-density tag single nucleotide polymorphism (SNP) genotyping. Association with 557 SNPs was tested using the transmission disequilibrium test in 270 nuclear pedigrees selected from an ongoing ADHD genetic study that includes all disease subtypes. RESULTS SNPs in seven genes including SLC1A3, SLC6A3, HTR4, ADRA1A, HTR2A, SNAP25, and COMT showed a nominal level of association with ADHD (P values <0.05), but none remained significant after a stringent correction for the total number of tests performed. CONCLUSION The strongest signal emerged from SNPs in the promoter region (rs3808585) and in an intron (rs17426222, rs4732682, rs573514) of ADRA1A, all located within the same haplotype block. Some of the SNPs in HTR2A and COMT have already been reported by others, whereas other SNPs will need confirmation in independent samples.
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27
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Gizer IR, Ficks C, Waldman ID. Candidate gene studies of ADHD: a meta-analytic review. Hum Genet 2009; 126:51-90. [PMID: 19506906 DOI: 10.1007/s00439-009-0694-x] [Citation(s) in RCA: 688] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Accepted: 05/27/2009] [Indexed: 02/07/2023]
Affiliation(s)
- Ian R Gizer
- Department of Genetics, University of North Carolina at Chapel Hill, 120 Mason Farm Road, Room 5015 Genetic Medicine Building CB 7264, Chapel Hill, NC 27599-7264, USA.
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Crews N, Wittwer CT, Montgomery J, Pryor R, Gale B. Spatial DNA Melting Analysis for Genotyping and Variant Scanning. Anal Chem 2009; 81:2053-8. [DOI: 10.1021/ac801495w] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Niel Crews
- Departments of Mechanical Engineering and Pathology, University of Utah, Salt Lake City, Utah 84112
| | - Carl T. Wittwer
- Departments of Mechanical Engineering and Pathology, University of Utah, Salt Lake City, Utah 84112
| | - Jesse Montgomery
- Departments of Mechanical Engineering and Pathology, University of Utah, Salt Lake City, Utah 84112
| | - Rob Pryor
- Departments of Mechanical Engineering and Pathology, University of Utah, Salt Lake City, Utah 84112
| | - Bruce Gale
- Departments of Mechanical Engineering and Pathology, University of Utah, Salt Lake City, Utah 84112
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Gillath O, Shaver PR, Baek JM, Chun DS. Genetic correlates of adult attachment style. PERSONALITY AND SOCIAL PSYCHOLOGY BULLETIN 2008; 34:1396-405. [PMID: 18687882 DOI: 10.1177/0146167208321484] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Attachment theory attempts to explain effects of social experiences, not genes, on personality development. Most studies of the development of attachment insecurities support this emphasis on social experiences rather than genes, although there are exceptions. In the present study, the authors examine associations between attachment insecurities and particular genetic polymorphisms related to emotions and social behavior. They find that (a) anxious attachment is associated with a polymorphism of the DRD2 dopamine receptor gene, (b) avoidant attachment is associated with a polymorphism of the 5HT2A serotonin receptor gene, and (c) the rs53576 A polymorphism of the OXTR oxytocin receptor gene is not associated with attachment insecurities. These findings suggest that attachment insecurities are partially explained by particular genes, although there is still a great deal of individual difference variance that remains to be explained by other genes or social experiences.
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Laurin N, Lee J, Ickowicz A, Pathare T, Malone M, Tannock R, Kennedy JL, Schachar RJ, Barr CL. Association study for genes at chromosome 5p13-q11 in attention deficit hyperactivity disorder. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:600-5. [PMID: 18081024 DOI: 10.1002/ajmg.b.30654] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Linkage of attention deficit hyperactivity disorder (ADHD) to the short arm-centromeric region of chromosome 5 has been reported in multiple studies. The overlapping region (5p13-q11) contains a number of strong candidate genes for ADHD, based on their role in brain function or neurodevelopment. The aim of this study was to investigate some of the top candidates among these genes in relation to ADHD in a sample of 245 nuclear families from the Toronto area. We investigated the genes for the glial cell-derived neurotropic factor (GDNF), the fibroblast growth factor 10 (FGF10), islet-1 (ISL1), the hyperpolarized potassium channel (HCN1) and the integrin alpha 1 (ITGA1). In addition to these genes, we assessed the 3'region of the SLC1A3 gene, a glutamate transporter implicated in ADHD by a previous association study. A total of 36 polymorphisms were selected across the six genes. We performed family-based association and haplotype analyses. ADHD is a dimensional disorder, with symptoms of inattention and hyperactivity-impulsivity therefore, we also conducted quantitative analysis in relation to symptom scores for both dimensions. Single marker and haplotype analyses yielded little evidence of association for any of the genes tested in this study. Moreover, we were unable to replicate the positive association findings reported for SLC1A3. Our results suggest that these six genes are unlikely to be susceptibility genes in the chromosome 5p13-q11 region and other genes should now be considered for priority study.
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Affiliation(s)
- Nancy Laurin
- Genetics and Development Division, The Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
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Affiliation(s)
- David E Nichols
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Purdue University, West Lafayette, Indiana 47906-2091, USA.
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Laurin N, Ickowicz A, Pathare T, Malone M, Tannock R, Schachar R, Kennedy JL, Barr CL. No evidence for genetic association between DARPP-32 (PP1R1B) polymorphisms and attention deficit hyperactivity disorder. Am J Med Genet B Neuropsychiatr Genet 2008; 147:339-42. [PMID: 17948899 DOI: 10.1002/ajmg.b.30604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) has a strong genetic basis, and evidence from human and animal studies suggests that a dopamine system dysfunction plays a role in the disorder pathophysiology. Several genes involved in dopamine neurotransmission have shown replicated genetic association with ADHD. These include the dopamine receptors D4 (DRD4), D5 (DRD5), and the dopamine transporter (DAT1) genes. Recently, evidence has also accumulated in favor of the dopamine receptor D1 gene (DRD1). The dopamine- and cAMP-regulated phosphoprotein of relative molecular mass of 32 kDa (DARPP-32) is a key component of dopamine signaling, acting as a converging point for several neurotransmitter systems influencing dopaminergic neurons and regulating a wide variety of downstream effectors. Here, we tested the DARPP-32 gene, PPP1R1B, for association with ADHD using four polymorphic markers selected across the gene in a sample of 255 ADHD families. We did not detect evidence of association of individual marker alleles and haplotype analysis did not reveal significant association in this sample of families. Moreover, we found no relationship between the same alleles or haplotypes and symptom scores of inattention or hyperactivity/impulsivity in these families using a quantitative approach. In conclusion, albeit a key regulatory role in dopamine signaling, our data do not support a major contribution of the DARPP-32 gene in ADHD.
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Affiliation(s)
- Nancy Laurin
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
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Abstract
Results of behavioral genetic and molecular genetic studies have converged to suggest that both genetic and nongenetic factors contribute to the development of attention deficit hyperactivity disorder (ADHD). Family, twin, and adoption studies provide compelling evidence that genes play a strong role in mediating susceptibility to ADHD. In contrast to a handful of genome-wide scans conducted thus far, many candidate gene studies of ADHD have produced substantial evidence implicating several genes in the etiology of the disorder. Yet, even these associations are small and consistent with the idea that the genetic vulnerability to ADHD is mediated by many genes of small effects. These small effects emphasize the need for future candidate gene studies to implement strategies that will provide enough statistical power to detect such small effects.
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Affiliation(s)
- Eric Mick
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Warren 705, 55 Fruit Street, Boston, MA 02114-2622, USA
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Wallis D, Russell HF, Muenke M. Review: Genetics of Attention Deficit/Hyperactivity Disorder. J Pediatr Psychol 2008; 33:1085-99. [DOI: 10.1093/jpepsy/jsn049] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Laurin N, Ickowicz A, Pathare T, Malone M, Tannock R, Schachar R, Kennedy JL, Barr CL. Investigation of the G protein subunit Galphaolf gene (GNAL) in attention deficit/hyperactivity disorder. J Psychiatr Res 2008; 42:117-24. [PMID: 17166517 PMCID: PMC4930670 DOI: 10.1016/j.jpsychires.2006.10.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 10/22/2006] [Accepted: 10/24/2006] [Indexed: 02/03/2023]
Abstract
The dopamine system plays an important role in the regulation of attention and motor behavior, subsequently, several dopamine-related genes have been associated with Attention Deficit/Hyperactivity Disorder (ADHD). Among them are the dopamine receptors D1 and D5 that mediate adenylyl cyclase activation through coupling with G(s)-like proteins. We thus hypothesized that the G(s)-like subunit Galpha(olf), expressed in D1-rich areas of the brain, contributes to the genetic susceptibility of ADHD. To evaluate the involvement of the Galpha(olf) gene, GNAL, in ADHD, we examined the inheritance pattern of 12 GNAL polymorphisms in 258 nuclear families ascertained through a proband with ADHD (311 affected children) using the transmission/disequilibrium test (TDT). Categorical analysis of individual marker alleles demonstrated biased transmission of one polymorphism in GNAL intron 3 (rs2161961; P=0.011). We also observed significant relationships between rs2161961 and dimensional symptoms of inattention and hyperactivity/impulsivity (P=0.003 and P=0.008). In addition, because of recent evidence of imprinting at the GNAL locus, secondary analyses were split into maternal and paternal transmissions to assess a contribution of parental effects. We found evidence of strong maternal effect, with preferential transmission of maternal alleles for rs2161961A (P=0.005) and rs8098539A (P=0.035). These preliminary findings suggest a possible contribution of GNAL in the susceptibility to ADHD, with possible involvement of parent-of-origin effects.
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Affiliation(s)
- Nancy Laurin
- Cell and Molecular Biology Division, Toronto Western Research Institute, University Health Network, Toronto, Ont., Canada
| | - Abel Ickowicz
- Department of Psychiatry, Brain and Behaviour Programme, The Hospital for Sick Children, Toronto, Ont., Canada
| | - Tejaswee Pathare
- Department of Psychiatry, Brain and Behaviour Programme, The Hospital for Sick Children, Toronto, Ont., Canada
| | - Molly Malone
- Division of Neurology, Brain and Behaviour Programme, The Hospital for Sick Children, Toronto, Ont., Canada
| | - Rosemary Tannock
- Department of Psychiatry, Brain and Behaviour Programme, The Hospital for Sick Children, Toronto, Ont., Canada
| | - Russell Schachar
- Department of Psychiatry, Brain and Behaviour Programme, The Hospital for Sick Children, Toronto, Ont., Canada
| | - James L. Kennedy
- Neurogenetics Section, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ont., Canada
| | - Cathy L. Barr
- Cell and Molecular Biology Division, Toronto Western Research Institute, University Health Network, Toronto, Ont., Canada
- Department of Psychiatry, Brain and Behaviour Programme, The Hospital for Sick Children, Toronto, Ont., Canada
- Corresponding author. Tel.: +1 416 603 5800x2744; fax: +1 416 603 5126. (C.L. Barr)
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Lee J, Laurin N, Crosbie J, Ickowicz A, Pathare T, Malone M, Tannock R, Kennedy JL, Schachar R, Barr CL. Association study of the brain-derived neurotropic factor (BDNF) gene in attention deficit hyperactivity disorder. Am J Med Genet B Neuropsychiatr Genet 2007; 144B:976-81. [PMID: 17918236 DOI: 10.1002/ajmg.b.30437] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental childhood psychiatric disorder. Brain-derived neurotropic factor (BDNF) has been suggested to play a role in the pathogenesis of ADHD and two family-based association studies demonstrated an association of BDNF polymorphisms with ADHD. The aim of the current study was to investigate the BDNF gene for association with ADHD in a large sample of families from Toronto. The transmission of three polymorphisms of the BDNF gene (rs6265, rs11030104, and rs2049046) was examined in 266 nuclear families ascertained through a proband with ADHD (315 affected children) using the transmission/disequilibrium test (TDT). In addition, we conducted quantitative analysis to assess the relationship between these marker alleles and the symptom dimensions of ADHD (inattention and hyperactivity/impulsivity) and cognitive measures of working memory. None of the individual marker alleles showed significant evidence of association with ADHD, dimensional symptom scores, or working memory ability in our sample of ADHD families. There was no significant evidence for biased transmission of individual haplotypes with frequency >10% (global chi2 for these three haplotypes: chi2 = 6.349, df = 3, P = 0.096). One uncommon haplotype (A-G-G; frequency 2.2%) showed a significant association with ADHD in the categorical (chi2 = 5.293, df = 1, P = 0.021) and quantitative analyses (parents' rated inattention: Z = -2.504, P = 0.012; and hyperactivity/impulsivity: Z = -2.651, P = 0.008). These results should be interpreted cautiously, however, because of the low haplotype frequency. In light of the evidence for an involvement of BDNF in ADHD, further analysis of the BDNF gene in ADHD is warranted.
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Affiliation(s)
- Jonghun Lee
- Cell and Molecular Biology Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
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Abstract
A limited number of studies have considered whether the activity of serotonin (5-hydroxytryptamine [5-HT]) contributes to the problems experienced by youngsters with attention-deficit/hyperactivity disorder (ADHD). The aim of this article is to review this work and propose interpretations. Peripheral measures of 5-HT and its metabolite do not point to a widespread association with the diagnosis. However, separate consideration of the major domains of dysfunction (motor activity, inattention and impulsivity) support a more differentiated assessment. The marked innervation of motor regions of the brain by 5-HT projections and the clear involvement of 5-HT systems in the control of locomotion in animals suggests a likely node for dysfunction in ADHD. The few relevant studies do not show evidence of this, but more attention should be accorded to the issue. The situation is different for attention-related processes; here, there are deficiencies in perceptual sensitivity and the appropriate designation of saliency to stimulation. These are attributable, in part, to altered 5-HT activity. Marked and opposite changes of 5-HT responsivity are associated with behavioral and cognitive impulsivity. There is also a growing series of studies demonstrating preferential transmission of various genetic markers for 5-HT receptors that are expressed in ADHD. Currently, the heterogeneity of methods in this young discipline restricts the possibilities of definition of these markers and the types of ADHD in which they are expressed.
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Affiliation(s)
- Robert D Oades
- Clinic for Child and Adolescent Psychiatry and Psychotherapy, Virchowstr 174, 45147 Essen, Germany.
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38
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Reprint of “Neurobiology of animal models of attention-deficit hyperactivity disorder”. J Neurosci Methods 2007; 166:I-XIV. [DOI: 10.1016/j.jneumeth.2006.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Revised: 12/04/2006] [Accepted: 12/14/2006] [Indexed: 11/22/2022]
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Russell VA. Neurobiology of animal models of attention-deficit hyperactivity disorder. J Neurosci Methods 2007; 161:185-98. [PMID: 17275916 DOI: 10.1016/j.jneumeth.2006.12.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Revised: 12/04/2006] [Accepted: 12/14/2006] [Indexed: 10/23/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a heterogeneous, highly heritable, disorder resulting from complex gene-gene and gene-environment interactions. The defining symptoms of hyperactivity, impulsivity and impaired sustained attention are not unique to ADHD. It is therefore not surprising that animals with distinctly different neural defects model the behavioural characteristics of the disorder. Consistent with ADHD being a developmental disorder, animal models are either genetic (spontaneously hypertensive rats (SHR), dopamine transporter (DAT) knock-out mice, SNAP-25 mutant mice, mice expressing a mutant thyroid receptor) or have suffered an insult to the central nervous system during the early stages of development (anoxia, 6-hydroxydopamine). It appears that neural transmission is impaired by either direct disruption of dopaminergic transmission or a more general impairment of neurotransmission that gives rise to compensatory changes in monoaminergic systems that are not sufficient to completely normalize neural function. In general, results obtained with animal studies suggest that dopamine neurons are functionally impaired. However, evidence obtained from some animal models suggests that the noradrenergic and serotonergic neurotransmitter systems may be the target of drugs that ameliorate ADHD symptoms.
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Affiliation(s)
- Vivienne Ann Russell
- Department of Human Biology, University of Cape Town, Anzio Road, Observatory 7925, South Africa.
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Laurin N, Feng Y, Ickowicz A, Pathare T, Malone M, Tannock R, Schachar R, Kennedy JL, Barr CL. No preferential transmission of paternal alleles at risk genes in attention-deficit hyperactivity disorder. Mol Psychiatry 2007; 12:226-9. [PMID: 17325714 DOI: 10.1038/sj.mp.4001936] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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41
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Guimarães APM, Zeni C, Polanczyk GV, Genro JP, Roman T, Rohde LA, Hutz MH. Serotonin genes and attention deficit/hyperactivity disorder in a Brazilian sample: preferential transmission of the HTR2A 452His allele to affected boys. Am J Med Genet B Neuropsychiatr Genet 2007; 144B:69-73. [PMID: 16958038 DOI: 10.1002/ajmg.b.30400] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders of childhood. The role of genetic factors in its etiology is strongly supported by family, adoption, and twin studies. Low serotonin activity has been associated in both animal and human studies with measures of impulsivity, aggression, and disinhibited behaviors, which make genes from the serotonin system reasonable candidates for ADHD susceptibility. In the present study, we investigated a polymorphism in the promoter region of the serotonin transporter (SLC6A4) and two polymorphisms (-1438 A > G and His452Tyr) in the serotonin 5-HTR2A receptor gene using family based association analyses in a sample of 243 Brazilian ADHD children and adolescents and their parents. No linkage disequilibrium between the two HTR2A polymorphisms was detected in this sample (P = 0.76). Considering several evidences from animal models for sexual dimorphism in serotonin genes expression, analyses were performed separately for the whole sample and for male probands. No evidences for biased transmissions of both HTR2A -1438 A > G and SLC6A4 polymorphisms to ADHD youths were observed. Preferential transmission of the HTR2A His452 allele was observed only in families with affected boys (P = 0.04). Our results suggest that findings from ADHD association studies for serotonin genes might be understood in the context of a gender effect, which may help to explain conflicting results in these association studies.
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Affiliation(s)
- Ana Paula M Guimarães
- Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Heiser P, Dempfle A, Friedel S, Konrad K, Hinney A, Kiefl H, Walitza S, Bettecken T, Saar K, Linder M, Warnke A, Herpertz-Dahlmann B, Schäfer H, Remschmidt H, Hebebrand J. Family-based association study of serotonergic candidate genes and attention-deficit/hyperactivity disorder in a German sample. J Neural Transm (Vienna) 2006; 114:513-21. [PMID: 17093889 DOI: 10.1007/s00702-006-0584-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Accepted: 09/27/2006] [Indexed: 12/20/2022]
Abstract
Alterations in the serotonergic pathway have been implicated in the pathogenesis of attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to investigate seven genetic variants in three genes (serotonin transporter (5-HTT), serotonin receptor 1B (5-HTR1B) and serotonin receptor 2A (5-HTR2A)), which have previously been shown to be associated with ADHD. The polymorphisms under investigation were the 5-HTTLPR, the VNTR in intron 2 and the 3'UTR SNP in 5-HTT, the 5-HTR1B variations 861G>C and 102T>C, and the 5-HTR2A variations His452Tyr and 1438G>A. We genotyped these variants in a sample of 102 families with 229 children with ADHD according to DSM-IV criteria. Among the affected children, 69% fulfilled criteria for the combined type, 27% for the predominantly inattentive type, and 4% for the predominantly hyperactive-impulsive type. Associations were tested by the pedigree transmission disequilibrium test (PDT). All investigated polymorphisms in serotonergic candidate genes showed no association to ADHD in our sample. Earlier studies of these polymorphisms had also shown inconsistent results, with some studies reporting significant associations and others demonstrating no association. This discordance between studies may reflect variation in patient ascertainment criteria, genetic heterogeneity, too low statistical power for the expected effects or false positive results in the initial reports. We cannot rule out the possibility that other variations in the investigated genes contribute to the etiology of ADHD.
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Affiliation(s)
- P Heiser
- Department of Child and Adolescent Psychiatry and Psychotherapy, Philipps-University, Marburg, Germany
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Li J, Wang Y, Zhou R, Zhang H, Yang L, Wang B, Faraone SV. Association between polymorphisms in serotonin 2C receptor gene and attention-deficit/hyperactivity disorder in Han Chinese subjects. Neurosci Lett 2006; 407:107-11. [PMID: 16959425 DOI: 10.1016/j.neulet.2006.08.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 07/10/2006] [Accepted: 08/10/2006] [Indexed: 11/28/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) is much more frequent in males than females, so several genes on the X chromosome (e.g., MAOA and MAOB) have been pursued as candidates for influencing risk for the disorder. HTR2C is also located on the X chromosome. In the current study, we examined the relationship between the C-759T and G-697C polymorphisms of HTR2C and ADHD in 488 Han Chinese families. Transmission Disequilibrium Test (TDT) analysis showed that the -759C allele, the -697G allele, and haplotype -759C/-697G were significantly over-transmitted to affected probands, while haplotypes -759C/-697C and -759T/-697C were under-transmitted. When families were divided into three subtypes according to the diagnosis of probands, the -697G allele and haplotype -759C/-697G were significantly over transmitted to ADHD-C probands, while haplotype -759T/-697C was under-transmitted to these individuals; however, no biased transmission of any allele or haplotype was observed for probands with ADHD-I, suggesting that different subtypes of ADHD have different genetic influences. Our findings highlight the need to explore the role of 5-HT2C receptor dysfunction in the pathogenesis of ADHD.
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Affiliation(s)
- Jun Li
- Institute of Mental Health, Peking University (Peking University sixth hospital), Beijing 100083, People's Republic of China
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44
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Dorval KM, Wigg KG, Crosbie J, Tannock R, Kennedy JL, Ickowicz A, Pathare T, Malone M, Schachar R, Barr CL. Association of the glutamate receptor subunit gene GRIN2B with attention-deficit/hyperactivity disorder. GENES BRAIN AND BEHAVIOR 2006; 6:444-52. [PMID: 17010153 PMCID: PMC4833492 DOI: 10.1111/j.1601-183x.2006.00273.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The glutamatergic signaling pathway represents an ideal candidate susceptibility system for attention-deficit/hyperactivity disorder (ADHD). Disruption of specific N-methyl-D-aspartate-type glutamate receptor subunit genes (GRIN1, 2A-D) in mice leads to significant alterations in cognitive and/or locomotor behavior including impairments in latent learning, spatial memory tasks and hyperactivity. Here, we tested for association of GRIN2B variants with ADHD, by genotyping nine single nucleotide polymorphisms (SNPs) in 205 nuclear families identified through probands with ADHD. Transmission of alleles from heterozygous parents to affected offspring was examined using the transmission/disequilibrium test. Quantitative trait analyses for the ADHD symptom dimensions [inattentive (IA) and hyperactive/impulsive (HI)] and cognitive measures of verbal working memory and verbal short-term memory were performed using the fbat program. Three SNPs showed significantly biased transmission (P < 0.05), with the strongest evidence of association found for rs2,284,411 (chi(2)= 7.903, 1 degree of freedom, P= 0.005). Quantitative trait analyses showed associations of these markers with both the IA and the HI symptom dimensions of ADHD but not with the cognitive measures of verbal short-term memory or verbal working memory. Our data suggest an association between variations in the GRIN2B subunit gene and ADHD as measured categorically or as a quantitatively distributed trait.
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Affiliation(s)
- K. M. Dorval
- Cell and Molecular Biology Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - K. G. Wigg
- Cell and Molecular Biology Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - J. Crosbie
- Brain and Behavior Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - R. Tannock
- Brain and Behavior Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - J. L. Kennedy
- Neurogenetics Section, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - A. Ickowicz
- Brain and Behavior Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - T. Pathare
- Brain and Behavior Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - M. Malone
- Brain and Behavior Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - R. Schachar
- Brain and Behavior Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - C. L. Barr
- Cell and Molecular Biology Division, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Brain and Behavior Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Corresponding author: C. L. Barr, Toronto Western Hospital, Main Pavilion, Rm 14-302, 399 Bathurst St, Toronto, Ontario, Canada M5T 2S8.
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45
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Wigg KG, Takhar A, Ickowicz A, Tannock R, Kennedy JL, Pathare T, Malone M, Schachar R, Barr CL. Gene for the serotonin transporter and ADHD: no association with two functional polymorphisms. Am J Med Genet B Neuropsychiatr Genet 2006; 141B:566-70. [PMID: 16856124 DOI: 10.1002/ajmg.b.30247] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Evidence from both human and animal studies implicates the serotonergic system in the development of attention-deficit hyperactivity disorder (ADHD) including positive association studies for several key serotonergic genes. The serotonin transporter (HTT) regulates the availability of serotonin by reuptake of the neurotransmitter from the synaptic cleft. Several studies have reported an association of this gene to ADHD, specifically the long variant of a common insertion/deletion polymorphism located in the promoter of this gene that results in increased transcription and higher HTT expression. An additional study found no evidence for an association with this polymorphism. Recently, an A/G single nucleotide polymorphism (SNP) was found within the promoter polymorphism with functional studies indicating that the long variant containing the G allele at this site behaves like the short variant. This previously unidentified functional change may have confounded earlier association studies. We investigated the relationship of several variants to ADHD: the promoter polymorphisms, SNP in the 3' untranslated region (3'UTR) with a reported association to ADHD and a rare, non-synonymous coding SNP. These polymorphisms were genotyped in 209 ADHD families identified through an affected proband. We did not find evidence for an association of these polymorphisms, or haplotypes of these polymorphisms, to ADHD in this sample.
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Affiliation(s)
- Karen G Wigg
- Department of Psychiatry, Cell and Molecular Division, The Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
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46
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Badcock C, Crespi B. Imbalanced genomic imprinting in brain development: an evolutionary basis for the aetiology of autism. J Evol Biol 2006; 19:1007-32. [PMID: 16780503 DOI: 10.1111/j.1420-9101.2006.01091.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We describe a new hypothesis for the development of autism, that it is driven by imbalances in brain development involving enhanced effects of paternally expressed imprinted genes, deficits of effects from maternally expressed genes, or both. This hypothesis is supported by: (1) the strong genomic-imprinting component to the genetic and developmental mechanisms of autism, Angelman syndrome, Rett syndrome and Turner syndrome; (2) the core behavioural features of autism, such as self-focused behaviour, altered social interactions and language, and enhanced spatial and mechanistic cognition and abilities, and (3) the degree to which relevant brain functions and structures are altered in autism and related disorders. The imprinted brain theory of autism has important implications for understanding the genetic, epigenetic, neurological and cognitive bases of autism, as ultimately due to imbalances in the outcomes of intragenomic conflict between effects of maternally vs. paternally expressed genes.
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Affiliation(s)
- C Badcock
- Department of Sociology, London School of Economics, London, UK
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47
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Li J, Kang C, Wang Y, Zhou R, Wang B, Guan L, Yang L, Faraone SV. Contribution of 5-HT2A receptor gene -1438A>G polymorphism to outcome of attention-deficit/hyperactivity disorder in adolescents. Am J Med Genet B Neuropsychiatr Genet 2006; 141B:473-6. [PMID: 16741915 DOI: 10.1002/ajmg.b.30320] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) typically emerges before 7 years of age and may persist into adolescence or adulthood. The adolescent outcome can be classified into four types, including non-remission, syndromatic remission, symptomatic remission, and functional remission. Genetic factors are believed to contribute to symptom stability and change across development, so adolescent outcome may be a sub-phenotype for molecular genetic studies of ADHD. Serotonin system genes are prime candidates for this sub-phenotype, since the development of this neurotransmitter system parallels the course of ADHD. The current study examined the association between adolescent outcome in ADHD and serotonin system genes, including the -1438A>G polymorphism of the serotonin 2A receptor gene (HTR2A) and the -759C>T polymorphism of the serotonin 2C receptor gene (HTR2C). The -1438A>G polymorphism was found to be related to remission in ADHD, especially functional remission (P = 0.029). Due to potential phenotypic and etiologic heterogeneity in ADHD, the results of this study must be replicated in additional samples before they can be generalized to other populations.
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Affiliation(s)
- Jun Li
- Institute of Mental Health, Peking University (Peking University sixth hospital), Beijing, People's Republic of China
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Li J, Wang Y, Zhou R, Wang B, Zhang H, Yang L, Faraone SV. No association of attention-deficit/hyperactivity disorder with genes of the serotonergic pathway in Han Chinese subjects. Neurosci Lett 2006; 403:172-5. [PMID: 16701945 DOI: 10.1016/j.neulet.2006.04.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 04/05/2006] [Accepted: 04/24/2006] [Indexed: 11/23/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a complex psychiatric syndrome with cardinal symptoms of inattention, hyperactivity and impulsivity, and is a significant risk factor for poor health outcomes in both adolescence and adulthood. Etiology is clearly multifactoral, with probable contributions from both genetic and environmental factors. The genetic contribution is prominent, with estimated heritability at about 0.80. Although effects in dopamine metabolism have long been implicated in the etiology of ADHD, the role for serotonin has gained more attention in recent years. The current study examined five variants in three serotonin genes [those that code for serotonin receptors 2A (HTR2A), 5A (HTR5A) and 6 (HTR6)] in a relatively large sample of ADHD nuclear families. The transmission disequilibrium test (TDT) and the extended transmission disequilibrium test (ETDT) were performed to test for evidence of distorted transmission of alleles or haplotypes. No significant biased transmission was observed. These results do not support a substantial role of these serotonin gene in ADHD, however, additional work may be warranted before this association is definitively discounted.
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Affiliation(s)
- Jun Li
- Institute of Mental Health, Peking University, Peking University sixth hospital, Beijing 100083, PR China
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Li J, Wang Y, Zhou R, Zhang H, Yang L, Wang B, Faraone SV. Association between tryptophan hydroxylase gene polymorphisms and attention deficit hyperactivity disorder in Chinese Han population. Am J Med Genet B Neuropsychiatr Genet 2006; 141B:126-9. [PMID: 16389593 DOI: 10.1002/ajmg.b.30260] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) is a severe behavioral disorder in children known to have a substantial genetic component. Prior studies have implicated serotonin genes in the etiology of ADHD but have not examined tryptophan hydroxylase (TPH), which is a rate-limiting enzyme in serotonin biosynthesis. The current study examined the relationship between the A218C and A-6526G polymorphisms of the TPH gene and ADHD. Three hundred sixty-two unrelated ADHD probands and their biological parents were recruited to participate in this study. No biased transmission of any allele of the two polymorphisms was observed using TDT analysis. However, haplotype analyses found that the rare 218A/-6526G haplotype was significantly not transmitted to probands with ADHD (chi(2) = 4.4995, P = 0.034), regardless of subtype. Although this finding for ADHD in the Chinese Han population.
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Affiliation(s)
- Jun Li
- Institute of Mental Health, Peking University (Peking University Sixth Hospital) Beijing, China
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Abstract
Over the past 15 years, considerable progress has been made in understanding the etiology of childhood Attention Deficit Hyperactivity Disorder (ADHD), largely due to the publication of numerous twin studies which are consistent in suggesting substantial genetic influences (i.e., heritabilities ranging from 60% to 90%), non-shared environmental influences that are small-to-moderate in magnitude (i.e., ranging from 10% to 40%), and little-to-no shared environmental influences. Following from these quantitative genetic findings, numerous molecular genetic studies of association and linkage between ADHD and a variety of candidate genes have been conducted during the past 10 years. The majority of the candidate genes studied underlie various facets of the dopamine, norepinephrine, and serotonin neurotransmitter systems, although the etiological role of candidate genes outside of neurotransmitter systems (e.g., involved in various aspects of brain and nervous system development) have also been examined. In this paper, we review recent findings from candidate gene studies of childhood ADHD and highlight those candidate genes for which associations are most replicable and which thus appear most promising. We conclude with a consideration of some of the emerging themes that will be important in future studies of the genetics of ADHD.
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