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Wongpaiboonwattana W, Plong-On O, Hnoonual A, Limprasert P. Significant associations between 5-hydroxytryptaminetransporter-linked promoter region polymorphisms of the serotonin transporter (solute carrier family 6 member 4) gene and Thai patients with autism spectrum disorder. Medicine (Baltimore) 2020; 99:e21946. [PMID: 32899028 PMCID: PMC7478716 DOI: 10.1097/md.0000000000021946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Autism spectrum disorder (ASD) is a form of pervasive developmental disorder manifested by impairment in social interactions and repetitive behaviors. Although genetic contribution is strongly suspected in autism, the specific genetic factors remain unidentified. Hyperserotoninemia has been reported in some autistic patients, and several studies have demonstrated an association between 5-hydroxytryptamine-transporter-linked promoter region (5-HTTLPR) polymorphisms and rs25531 single nucleotide polymorphism in the serotonin transporter gene (solute carrier family 6 member 4; SLC6A4) and ASD, indicating a possible involvement of the serotonin system in the etiology of ASD.To explore this situation further, a case-control association study of 5-HTTLPR and rs25531 polymorphisms on Thai ASD patients was conducted. A total of 188 ASD cases fulfilling the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) criteria (156 males and 32 females) and a total of 250 normal controls were recruited from the same ethnic backgrounds. 5-HTTLPR polymorphisms (Long, L; Short, S) and rs25531 (A/G) single nucleotide polymorphism were genotyped and compared between the patients and normal controls using chi-square statistics.The L/L genotype was more common in patients than in the controls (13.8% vs 5.2%, P = .006), and the LA haplotype was found in patients more than the controls (16.9% vs 12.2%, P = .048). When male patients were analyzed alone (156 individuals), the associations were also statistically significant with P = .017 for L/L genotype, and P = .019 for LA haplotype distribution.Our findings support previous reports suggesting an association between the 5-HTTLPR and rs25531 polymorphisms of SLC6A4 and patients with ASD.
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Affiliation(s)
| | - Oradawan Plong-On
- Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Areerat Hnoonual
- Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Pornprot Limprasert
- Faculty of Medicine, King Mongkut's Institute of Technology Ladkrabang, Bangkok
- Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
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Wegener Sleeswijk A, Heijungs R, Durston S. Tackling Missing Heritability by Use of an Optimum Curve: A Systematic Review and Meta-Analysis. Int J Mol Sci 2019; 20:ijms20205104. [PMID: 31618836 PMCID: PMC6829377 DOI: 10.3390/ijms20205104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/07/2019] [Accepted: 10/12/2019] [Indexed: 11/28/2022] Open
Abstract
Missing heritability is a common problem in psychiatry that impedes precision medicine approaches to autism and other heritable complex disorders. This proof-of-concept study uses a systematic review and meta-analysis of the association between variants of the serotonin transporter promoter (5-HTTLPR) and autism to explore the hypothesis that some missing heritability can be explained using an optimum curve. A systematic literature search was performed to identify transmission disequilibrium tests on the short/long (S/L) 5-HTTLPR polymorphism in relation to autism. We analysed five American, seven European, four Asian and two American/European samples. We found no transmission preference in the joint samples and in Europe, preferential transmission of S in America and preferential transmission of L in Asia. Heritability will be underestimated or missed in genetic association studies if two alternative genetic variants are associated with the same disorder in different subsets of a sample. An optimum curve, relating a multifactorial biological variable that incorporates genes and environment to a score for a human trait, such as social competence, can explain this. We suggest that variants of functionally related genes will sometimes appear in fixed combinations at both sides of an optimum curve and propose that future association studies should account for such combinations.
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Affiliation(s)
- Anneke Wegener Sleeswijk
- Department of Psychiatry, University Medical Center Utrecht Brain Center, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
| | - Reinout Heijungs
- Department of Econometrics and Operations Research, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands.
- Institute of Environmental Sciences, Department of Industrial Ecology, Leiden University, Einsteinweg 2, 2333 CC Leiden, The Netherlands.
| | - Sarah Durston
- Department of Psychiatry, University Medical Center Utrecht Brain Center, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
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Sener EF, Taheri S, Sahin MC, Bayramov KK, Marasli MK, Zararsiz G, Mehmetbeyoglu E, Oztop DB, Canpolat M, Canatan H, Ozkul Y. Altered Global mRNA Expressions of Pain and Aggression Related Genes in the Blood of Children with Autism Spectrum Disorders. J Mol Neurosci 2018; 67:89-96. [PMID: 30519864 DOI: 10.1007/s12031-018-1213-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/11/2018] [Indexed: 12/28/2022]
Abstract
Autism spectrum disorder (ASD) is characterized by repetitive stereotypic behaviors, restricted interests, social withdrawal, and communication deficits. Aggression and insensitivity to pain are largely unexplained in these cases. We analyzed nine mRNA expressions of the candidate genes related to aggression and insensitivity to pain in the peripheral blood of patients with ASD. Whole blood samples were obtained from 40 autistic patients (33 boys, 7 girls) and 50 age- and sex-matched controls (37 boys and 13 girls) to isolate RNA. Gene expression was assessed by quantitative Real-Time PCR (qRT-PCR) in the Erciyes University Genome and Stem Cell Center (GENKOK). All of the gene expressions except CRHR1 and SLC6A4 were found to be statistically different between the ASD patients and controls. Gene expression also differed according to gender. Alterations in the mRNA expression patterns of the HTR1E, OPRL1, OPRM1, TACR1, PRKG1, SCN9A and DRD4 genes provide further evidence for a relevant effect of the respective candidate genes on the pathophysiology of ASD. Future studies may determine the sensitivity of these candidate markers in larger samples including further neuropsychiatric diagnosis.
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MESH Headings
- Aggression
- Autism Spectrum Disorder/blood
- Autism Spectrum Disorder/genetics
- Autism Spectrum Disorder/physiopathology
- Biomarkers/blood
- Child, Preschool
- Cyclic GMP-Dependent Protein Kinase Type I/genetics
- Cyclic GMP-Dependent Protein Kinase Type I/metabolism
- Female
- Humans
- Male
- NAV1.7 Voltage-Gated Sodium Channel/genetics
- NAV1.7 Voltage-Gated Sodium Channel/metabolism
- Pain Perception
- RNA, Messenger/blood
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Serotonin, 5-HT1A/genetics
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptors, Dopamine D4/genetics
- Receptors, Dopamine D4/metabolism
- Receptors, Opioid/genetics
- Receptors, Opioid/metabolism
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Affiliation(s)
- Elif Funda Sener
- Department of Medical Biology, Erciyes University Medical Faculty , 38039, Kayseri, Turkey.
- Erciyes University Genome and Stem Cell Center (GENKOK), 38039, Kayseri, Turkey.
| | - Serpil Taheri
- Department of Medical Biology, Erciyes University Medical Faculty , 38039, Kayseri, Turkey
- Erciyes University Genome and Stem Cell Center (GENKOK), 38039, Kayseri, Turkey
| | | | | | | | - Gokmen Zararsiz
- Department of Biostatistics, Erciyes University Medical Faculty , 38039, Kayseri, Turkey
| | - Ecmel Mehmetbeyoglu
- Department of Medical Biology, Erciyes University Medical Faculty , 38039, Kayseri, Turkey
- Erciyes University Genome and Stem Cell Center (GENKOK), 38039, Kayseri, Turkey
| | - Didem Behice Oztop
- Department of Child and Adolescent Psychiatry, Ankara University Medical Faculty , Ankara, Turkey
| | - Mehmet Canpolat
- Department of Child Neurology, Erciyes University Medical Faculty, 38039, Kayseri, Turkey
| | - Halit Canatan
- Department of Medical Biology, Erciyes University Medical Faculty , 38039, Kayseri, Turkey
| | - Yusuf Ozkul
- Department of Medical Genetics, Erciyes University Medical Faculty, 38039, Kayseri, Turkey
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Yang PY, Menga YJ, Li T, Huang Y. Associations of endocrine stress-related gene polymorphisms with risk of autism spectrum disorders: Evidence from an integrated meta-analysis. Autism Res 2017; 10:1722-1736. [PMID: 28656683 DOI: 10.1002/aur.1822] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/12/2017] [Accepted: 05/23/2017] [Indexed: 02/05/2023]
Abstract
Autism spectrum disorders (ASD) are related to serotonin transporter (5-HTT) and catechol-O-methyl transferase (COMT) as two most monoaminergic polymorphic variations. However, multiple studies assessing rs4680 and 5-HTTLPR variants in ASD have reported inconsistent results. Therefore, we conducted an integrated meta-analysis to combine case-control and transmission/disequilibrium test (TDT) studies to determine whether COMT and 5-HTT are associated with ASD. We searched multiple electronic databases (PubMed, EmBase and Web of Science) to identify studies assessing the rs4680 and 5-HTTLPR variants in ASD from Jan 1997 to Dec 2016. Then allelic data from case-control and TDT studies were analyzed by the Catmap package in the R software. A total of 5 studies were eligible for the meta-analysis of rs4680, including 3 case-control, 1 TDT and 1 TDT & case-control studies. Meanwhile, 22 studies of 5-HTTLPR were available, including 16 TDT, 4 case-control and 2 TDT & case-control studies. The current meta-analysis included 814 ASD cases, 741 controls and 311 families related to rs4680; 749 ASD cases, 1,118 controls and 1,861 families relevant to 5-HTTLPR were also evaluated. For rs4680, the pooled OR was 1.18 (95% CI = 0.87-1.59, P = 0.29, Pheterogeneity < 0.00001). There was no significant association of rs4680 with risk of ASD between the two subgroups. For 5-HTTLPR, the pooled OR was 1.05 (95% CI = 0.92-1.20, P = 0.4652, Pheterogeneity < 0.00001). Meanwhile, we found no significant risk in individual case-control or TDT studies. The above findings indicated that neither COMT rs4680 nor 5-HTT 5-HTTLPR polymorphism significantly affects ASD risk. Autism Res 2017, 10: 1722-1736. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY Our results showed no evidence of significant association of either COMT rs4680 or 5-HTT 5-HTTLPR variants with ASD, showing that these two genes may not be major susceptible genetic factors in ASD occurrence, and may have a reciprocal action with each other in combination with environmental factors. These findings further provide evidence that a single gene variant may not dictate autism occurrence, but possibly contributes to a specific phenotype or subtype of ASD.
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Affiliation(s)
- Ping-Yuan Yang
- Mental Health Center, West China Hospital of Sichuan University, Chengdu, China
| | - Ya-Jing Menga
- Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Tao Li
- Mental Health Center, West China Hospital of Sichuan University, Chengdu, China.,Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Yi Huang
- Mental Health Center, West China Hospital of Sichuan University, Chengdu, China.,Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
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Watanabe SY, Iga JI, Numata S, Umehara H, Nishi A, Kinoshita M, Inoshita M, Ohmori T. Polymorphism in the promoter of the gene for the serotonin transporter affects the age of onset of major depressive disorder in the Japanese population. J Affect Disord 2015; 183:156-8. [PMID: 26005777 DOI: 10.1016/j.jad.2015.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 04/03/2015] [Accepted: 05/07/2015] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Recent research has suggested that a functional polymorphism in the promoter region of the serotonin transporter gene (serotonin transporter-linked polymorphic region, 5HTTLPR) may be implicated in gene-environment interactions leading to major depressive disorder (MDD). METHODS Our study examined the association between 5HTTLPR and clinical variables of MDD in the Japanese population. We genotyped 5HTTLPR in 216 patients with MDD and 213 age- and sex-matched controls. RESULTS The genotype distributions and allele frequencies were similar in the patients and controls. When the relationships between the polymorphism and several clinical variables (i.e., age of onset, number of episodes, presence of psychotic features, suicidal behavior, and family history) were examined, the dose of the long (l) allele had significant effects on the age of onset. CONCLUSION These results suggest that 5HTTLPR may not be entirely related to the development of MDD but may be related to the age of onset of MDD, which may be due to gene-environment interactions in the Japanese population. LIMITATIONS Because of the low frequencies of psychotic features and suicidal behavior, our results must be treated with caution until they are replicated in larger numbers of Japanese samples. MDD patients did not undergo a structured interview. Clinical information from the medical records may have not been complete.
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Affiliation(s)
- Shin-ya Watanabe
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Jun-ichi Iga
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan.
| | - Shusuke Numata
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Hidehiro Umehara
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Akira Nishi
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Makoto Kinoshita
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Masatoshi Inoshita
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Tetsuro Ohmori
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
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Jaiswal P, Mohanakumar KP, Rajamma U. Serotonin mediated immunoregulation and neural functions: Complicity in the aetiology of autism spectrum disorders. Neurosci Biobehav Rev 2015; 55:413-31. [PMID: 26021727 DOI: 10.1016/j.neubiorev.2015.05.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 12/19/2022]
Abstract
Serotonergic system has long been implicated in the aetiology of autism spectrum disorders (ASD), since platelet hyperserotonemia is consistently observed in a subset of autistic patients, who respond well to selective serotonin reuptake inhibitors. Apart from being a neurotransmitter, serotonin functions as a neurotrophic factor directing brain development and as an immunoregulator modulating immune responses. Serotonin transporter (SERT) regulates serotonin level in lymphoid tissues to ensure its proper functioning in innate and adaptive responses. Immunological molecules such as cytokines in turn regulate the transcription and activity of SERT. Dysregulation of serotonergic system could trigger signalling cascades that affect normal neural-immune interactions culminating in neurodevelopmental and neural connectivity defects precipitating behavioural abnormalities, or the disease phenotypes. Therefore, we suggest that a better understanding of the cross talk between serotonergic genes, immune systems and serotonergic neurotransmission will open wider avenues to develop pharmacological leads for addressing the core ASD behavioural deficits.
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Affiliation(s)
- Preeti Jaiswal
- Manovikas Biomedical Research and Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata 700 107, India
| | - Kochupurackal P Mohanakumar
- Division of Cell Biology & Physiology, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata 700 032, India
| | - Usha Rajamma
- Manovikas Biomedical Research and Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata 700 107, India.
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7
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Jaiswal P, Guhathakurta S, Singh AS, Verma D, Pandey M, Varghese M, Sinha S, Ghosh S, Mohanakumar KP, Rajamma U. SLC6A4 markers modulate platelet 5-HT level and specific behaviors of autism: a study from an Indian population. Prog Neuropsychopharmacol Biol Psychiatry 2015; 56:196-206. [PMID: 25261775 DOI: 10.1016/j.pnpbp.2014.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 09/17/2014] [Accepted: 09/17/2014] [Indexed: 10/24/2022]
Abstract
Presence of platelet hyperserotonemia and effective amelioration of behavioral dysfunctions by selective serotonin reuptake inhibitors (SSRI) in autism spectrum disorders (ASD) indicate that irregularities in serotonin (5-HT) reuptake and its homeostasis could be the basis of behavioral impairments in ASD patients. SLC6A4, the gene encoding serotonin transporter (SERT) is considered as a potential susceptibility gene for ASD, since it is a quantitative trait locus for blood 5-HT levels. Three functional polymorphisms, 5-HTTLPR, STin2 and 3'UTR-SNP of SLC6A4 are extensively studied for possible association with the disorder, with inconclusive outcome. In the present study, we investigated association of these polymorphisms with platelet 5-HT content and symptoms severity as revealed by childhood autism rating scale in ASD children from an Indian population. Higher 5-HT level observed in ASD was highly significant in children with heterozygous and homozygous genotypes comprising of minor alleles of the markers. Quantitative transmission disequilibrium test demonstrated significant genetic effect of STin2 allele as well as STin2/3'UTR-SNP and 5-HTTLPR/3'UTR-SNP haplotypes on 5-HT levels, but no direct association with overall CARS score and ASD phenotype. Significant genetic effect of the markers on specific behavioral phenotypes was observed for various sub-phenotypes of CARS in quantitative trait analysis. Even though the 5-HT level was not associated with severity of behavioral CARS score, a significant negative relationship was observed for 5-HT levels and level and consistency of intellectual response and general impression in ASD children. Population-based study revealed higher distribution of the haplotype 10/G of STin2/3'UTR-SNP in male controls, suggesting protective effect of this haplotype in male cases. Overall results of the study suggest that SLC6A4 markers have specific genetic effect on individual ASD behavioral attributes, might be through the modulation of 5-HT content.
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Affiliation(s)
- Preeti Jaiswal
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Subhrangshu Guhathakurta
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Asem Surindro Singh
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Deepak Verma
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Mritunjay Pandey
- Lab of Clinical & Experimental Neurosciences, Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Jadavpur, Kolkata, India
| | - Merina Varghese
- Lab of Clinical & Experimental Neurosciences, Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Jadavpur, Kolkata, India
| | - Swagata Sinha
- Out-Patients Department, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Saurabh Ghosh
- Human Genetics Unit, Indian Statistical Institute, 203 BT Road, Kolkata, India
| | - Kochupurackal P Mohanakumar
- Lab of Clinical & Experimental Neurosciences, Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Jadavpur, Kolkata, India
| | - Usha Rajamma
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India.
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8
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Li X, Zou H, Brown WT. Genes associated with autism spectrum disorder. Brain Res Bull 2012; 88:543-52. [PMID: 22688012 DOI: 10.1016/j.brainresbull.2012.05.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 05/31/2012] [Indexed: 01/06/2023]
Abstract
Autism spectrum disorder (ASD) is a heterogeneous grouping of neurodevelopmental disorders characterized by impairment in social interaction, verbal communication and repetitive/stereotypic behaviors. Much evidence suggests that ASD is multifactorial with a strong genetic basis, but the underlying mechanisms are far from clear. Recent advances in genetic technologies are beginning to shed light on possible etiologies of ASD. This review discusses current evidence for several widely studied candidate ASD genes, as well as various rare genes that supports their relationship to the etiology of ASD. The majority of the data are based on molecular, cytogenetic, linkage and association studies of autistic subjects, but newer methods, including whole-exome sequencing, are also beginning to make significant contributions to our understanding of autism.
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Affiliation(s)
- Xiaohong Li
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, New York, NY 10314, United States.
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9
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Gross C, Berry-Kravis EM, Bassell GJ. Therapeutic strategies in fragile X syndrome: dysregulated mGluR signaling and beyond. Neuropsychopharmacology 2012; 37:178-95. [PMID: 21796106 PMCID: PMC3238060 DOI: 10.1038/npp.2011.137] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/17/2011] [Accepted: 06/17/2011] [Indexed: 01/11/2023]
Abstract
Fragile X syndrome (FXS) is an inherited neurodevelopmental disease caused by loss of function of the fragile X mental retardation protein (FMRP). In the absence of FMRP, signaling through group 1 metabotropic glutamate receptors is elevated and insensitive to stimulation, which may underlie many of the neurological and neuropsychiatric features of FXS. Treatment of FXS animal models with negative allosteric modulators of these receptors and preliminary clinical trials in human patients support the hypothesis that metabotropic glutamate receptor signaling is a valuable therapeutic target in FXS. However, recent research has also shown that FMRP may regulate diverse aspects of neuronal signaling downstream of several cell surface receptors, suggesting a possible new route to more direct disease-targeted therapies. Here, we summarize promising recent advances in basic research identifying and testing novel therapeutic strategies in FXS models, and evaluate their potential therapeutic benefits. We provide an overview of recent and ongoing clinical trials motivated by some of these findings, and discuss the challenges for both basic science and clinical applications in the continued development of effective disease mechanism-targeted therapies for FXS.
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Affiliation(s)
- Christina Gross
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Elizabeth M Berry-Kravis
- Departments of Pediatrics, Neurology, and Biochemistry, Rush University Medical Center, Chicago, IL, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
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Sghendo L, Mifsud J. Understanding the molecular pharmacology of the serotonergic system: using fluoxetine as a model. ACTA ACUST UNITED AC 2011; 64:317-25. [PMID: 22309263 DOI: 10.1111/j.2042-7158.2011.01384.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Serotonin is a monoamine neurotransmitter that is widely distributed in the body and plays an important role in a variety of psychological and other body functions such as mood, sexual desire and function, appetite, sleep, memory and learning, temperature regulation and social behaviour. This review will assess the use of fluoxetine, one of the most commonly used selective serotonin reuptake inhibitors, as a model for understanding the molecular pharmacology of the serotoninergic system. KEY FINDINGS Seven serotonin receptor families have been discovered to date. All serotonin receptors, except 5-HT(3), are G-protein coupled, seven transmembrane receptors that activate an intracellular second messenger cascade. The 5-HT(3) receptor is a ligand-gated ion channel. Furthermore, 5-HT(1A) receptors are known as autoreceptors since their stimulation inhibits the release serotonin in nerve terminals. A transporter protein found in the plasma membrane of serotonergic neurones is responsible for the reuptake of this neurotransmitter. Selective serotonin reuptake inhibitors, such as fluoxetine, act primarily at the serotonin transporter protein and have limited, if any, reaction with other neurotransmitter systems. Selective serotonin reuptake inhibitors appear to bind with the serotonin transporter with different rates of occupancy, duration and potency. SUMMARY The following review focuses on the interaction of serotonin with this membrane transporter in the body and assesses the use of fluoxetine as a reference drug in the understanding of this interaction.
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Affiliation(s)
- Lino Sghendo
- Department of Clinical Pharmacology and Therapeutics, University of Malta, Msida, Malta
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11
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Margoob MA, Mushtaq D. Serotonin transporter gene polymorphism and psychiatric disorders: is there a link? Indian J Psychiatry 2011; 53:289-99. [PMID: 22303036 PMCID: PMC3267339 DOI: 10.4103/0019-5545.91901] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Though still in infancy, the field of psychiatric genetics holds great potential to contribute to the development of new diagnostic and therapeutic options to treat these disorders. Among a large number of existing neurotransmitter systems, the serotonin system dysfunction has been implicated in many psychiatric disorders and therapeutic efficacy of many drugs is also thought to be based on modulation of serotonin. Serotonin transporter gene polymorphism is one of the most extensively studied polymorphisms in psychiatric behavioral genetics. In this article, we review the status of evidence for association between the serotonin gene polymorphism and some common mental disorders like affective disorders, post-traumatic stress disorder, obsessive-compulsive disorder, suicide, autism, and other anxiety and personality disorders. Going beyond traditional association studies, gene-environment interaction, currently gaining momentum, is also discussed in the review. While the existing information of psychiatric genetics is inadequate for putting into practice genetic testing in the diagnostic work-up of the psychiatric patient, if consistent in future research attempts, such results can be of great help to improve the clinical care of a vast majority of patients suffering from such disorders.
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Affiliation(s)
- Mushtaq A Margoob
- Department of Psychiatry, Institute of Mental Health and Neurosciences-Kashmir, Kashmir, India.
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Arieff Z, Kaur M, Gameeldien H, van der Merwe L, Bajic VB. 5-HTTLPR Polymorphism: Analysis in South African Autistic Individuals. Hum Biol 2010; 82:291-300. [DOI: 10.3378/027.082.0303] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Influence of the 5-HTTLPR polymorphism and environmental risk factors in a Brazilian sample of patients with autism spectrum disorders. Brain Res 2009; 1267:9-17. [DOI: 10.1016/j.brainres.2009.02.072] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 02/21/2009] [Accepted: 02/28/2009] [Indexed: 11/19/2022]
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Guhathakurta S, Sinha S, Ghosh S, Chatterjee A, Ahmed S, Gangopadhyay PK, Usha R. Population-based association study and contrasting linkage disequilibrium pattern reveal genetic association of SLC6A4 with autism in the Indian population from West Bengal. Brain Res 2008; 1240:12-21. [DOI: 10.1016/j.brainres.2008.08.063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 06/23/2008] [Accepted: 08/24/2008] [Indexed: 12/11/2022]
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Huang CH, Santangelo SL. Autism and serotonin transporter gene polymorphisms: a systematic review and meta-analysis. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:903-13. [PMID: 18286633 DOI: 10.1002/ajmg.b.30720] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The serotonin transporter gene (5-HTT) plays a crucial role in serotonergic neurotransmission and has been found to be associated, with varying degrees of significance, with many diseases, including autism. Prior association studies of autism have yielded conflicting results regarding the association between two common 5-HTT polymorphisms, the promoter insertion/deletion (5-HTTLPR) and the intron 2 VNTR (STin2 VNTR). We conducted a systematic review and meta-analysis to test the following hypotheses: (i) there is an association between autism and either or both of the 5-HTTLPR and STin2 VNTR polymorphisms, and (ii) the S allele of 5-HTTLPR and/or the STin2.12 allele of the VNTR are the specific risk alleles for autism. All published family-based and population based studies were examined to determine the overall strength of association between 5-HTT polymorphisms and autism. After exclusion of studies with overlapping samples and studies whose data did not allow for calculation of an odds ratio, 16 studies were included for final analyses, all but two of which used a family-based design. The meta-analysis failed to find a significant overall association between either of the 5-HTT polymorphisms examined and autism. Further, no allelic transmission distortion was found when studies of simplex (11 studies) and multiplex (3 studies) family samples were analyzed separately. However, there was significant heterogeneity by ethnicity; family based studies of US mixed population samples showed preferential transmission of the S allele of 5-HTTLPR (S allele:L allele = 247:183), while there was no allelic distortion among the family-based studies of European and Asian samples.
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Affiliation(s)
- Christine H Huang
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
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Intersubjectivity, affective neuroscience, and the neurobiology of autistic spectrum disorders: a systematic review. Keio J Med 2008; 57:15-36. [PMID: 18382122 DOI: 10.2302/kjm.57.15] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intersubjectivity is an approach to the study of social interaction viewed from a perspective which rejects the view that reducing any such analysis to study at the level of the individual is adequate to address the issues of social functioning. It also stresses the view that social processes cannot be reduced to cognitive ones - most of the important questions in the study of developmental psychopathology deal with issues which have commonality with many other species and are patent well before the ontological emergence of 'cognitive' abilities. In this paper we review the evidence in this area, and discuss a range of issues relevant to autistic spectrum disorders. We focus in particular on social interaction; the role of the Intrinsic Motive Formation and recent work on mirror neurons in autism; genetic and teratogenic factors in the genesis of autism; and the role of a number of biological factors in pathogenesis - tryptophan; vitamin B12; sterol metabolism; glutamate and GABA; and the Fragile-X expansion.
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Cho IH, Yoo HJ, Park M, Lee YS, Kim SA. Family-based association study of 5-HTTLPR and the 5-HT2A receptor gene polymorphisms with autism spectrum disorder in Korean trios. Brain Res 2007; 1139:34-41. [PMID: 17280648 DOI: 10.1016/j.brainres.2007.01.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 12/19/2006] [Accepted: 01/02/2007] [Indexed: 11/25/2022]
Abstract
The potential role of the serotoninergic system in the development of autistic disorder has long been suggested based on the observation of hyperserotoninemia in autistic subjects and the results of drug treatment studies. Promoter region polymorphisms (5-HTTLPR) of the serotonin transporter gene (SLC6A4) and the 5-HT2A receptor gene (HTR2A) have been studied as potential candidate genes in autism spectrum disorder (ASD). The objective of this family-based linkage/association study is to evaluate the relationship between ASD and 5-HTTLPR as well as that between some SNPs of HTR2A and ASD in Korean trios by using the transmission disequilibrium test (TDT). Genotyping was performed for 5-HTTLPR and two single nucleotide polymorphisms (SNPs) (-1438G/A and 102T/C) of HTR2A. The TDT, linkage disequilibrium (LD) analysis and haplotype analysis were performed. This study comprised 126 complete trios of ASD patients and both parents. With regard to the transmission of 5-HTTLPR, the long allelic variant was preferentially transmitted in the ASD subjects. Based on the TDT results, there was no significant difference in the transmission of the two SNPs of HTR2A. However, in the results of the haplotype analysis, the AT haplotype demonstrated significant evidence of association with autism. The global chi(2) test for haplotype transmission revealed a significant association between HTR2A and autism. Although we identified a significant association between ASD and 5-HTTLPR as well as between ASD and HTR2A, it cannot exclude the chance finding because of the low level of statistical significance and relatively small power. We believe that further studies are required to examine the relationship between serotonin-related genes and the behavioral phenotypes of ASD in the Korean population.
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Affiliation(s)
- In Hee Cho
- Department of Psychiatry, Gachon University of Medicine and Science, 1198 Guwol-Dong, Namdong-Gu, Incheon, 405-760, Republic of Korea
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Abstract
Twin and family studies in autistic disorders (AD) have elucidated a high heritability of the narrow and broad phenotype of AD. In this review on the genetics of AD, we will initially delineate the phenotype of AD and discuss aspects of differential diagnosis, which are particularly relevant with regard to the genetics of autism. Cytogenetic and molecular genetic studies will be presented in detail, and the possibly involved aetiopathological pathways will be described. Implications of the different genetic findings for genetic counselling will be mentioned.
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Affiliation(s)
- C M Freitag
- Department of Child and Adolescent Psychiatry, Saarland University Hospital, Homburg, Germany.
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Guhathakurta S, Ghosh S, Sinha S, Chatterjee A, Ahmed S, Chowdhury SR, Gangopadhyay PK, Ghosh S, Singh M, Usha R. Serotonin transporter promoter variants: Analysis in Indian autistic and control population. Brain Res 2006; 1092:28-35. [PMID: 16674932 DOI: 10.1016/j.brainres.2006.03.078] [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: 05/24/2005] [Revised: 02/28/2006] [Accepted: 03/22/2006] [Indexed: 10/24/2022]
Abstract
Serotonin transporter (5-HTT) is a transmembrane protein belonging to Na+/Cl- dependent membrane transporter family and transports 5-HT across the membranes of presynaptic neurons. 5-HTT-linked polymorphic region (5-HTTLPR) gained much interest because of the differential regulation of expression and activity of 5-HTT by its various genotypes. A population-based study has been conducted on 5-HTTLPR with 358 individuals, which included 79 autistic probands, 136 parents, and 143 controls from two subpopulations of east and northeast regions of India. The genotypic frequencies of all the groups conform to Hardy-Weinberg equilibrium. With the finding of efficacy of serotonin reuptake inhibitors in ameliorating ritualistic behavior in autistic disorder, 5-HTT emerged as a putative candidate gene for autism and association studies have been carried out in different ethnic populations. But these studies were inconclusive due to conflicting results on association. Because such a study has never been performed in the Indian population, we have tested the possible involvement of 5-HTTLPR polymorphism with autism. The present study failed to establish any association or linkage of 5-HTTLPR with autism in the Indian population by case-control studies (chi2 = 1.314, P = 0.63) and family-based approaches (TDT chi2 = 0.22, P = 0.64 and HHRR-chi2 = 0.25, P = 0.61). However, when a meta-analysis of all the available TDT data, inclusive of the present study is carried out, we observed a significant preferential transmission of S-allele from parents to the affected offspring (chi2 = 7.51, P = 0.006) indicating an association of 5-HTTLPR with autism.
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Affiliation(s)
- Subhrangshu Guhathakurta
- Manovikas Biomedical Research and Diagnostic Centre, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata 700 107, India
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