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Nemoda Z, Angyal N, Tarnok Z, Birkas E, Bognar E, Sasvari-Szekely M, Gervai J, Lakatos K. Differential Genetic Effect of the Norepinephrine Transporter Promoter Polymorphisms on Attention Problems in Clinical and Non-clinical Samples. Front Neurosci 2019; 12:1051. [PMID: 30692908 PMCID: PMC6339888 DOI: 10.3389/fnins.2018.01051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/27/2018] [Indexed: 11/15/2022] Open
Abstract
Among the monoaminergic modulatory neurotransmitters, norepinephrine is involved in task orienting, hence noradrenergic genetic variants have been studied in connection to attentional processes. The role of this catecholamine system is also highlighted by the selective norepinephrine transporter blocking atomoxetine, which has proved to be effective in the pharmacological treatment of Attention Deficit Hyperactivity Disorder (ADHD). In the present genetic association study three single nucleotide polymorphisms (rs28386840, rs2242446, rs3785143 SNPs) were analyzed from the 5′ region of the norepinephrine transporter (NET, SLC6A2) gene, which have been linked to ADHD previously. Attention problems scores of the mother-rated Child Behavior Checklist (CBCL) were used in separate analyses of 88 preschoolers (59.1% male, 6 years of age) recruited from the general population and 120 child psychiatry patients with ADHD diagnosis (85.8% male, age: 9.8 ± 2.9). The NET SNPs showed associations with attention problems, but the direction was different in the two groups. Regarding the promoter variant rs28386840, which showed the most consistent association, the T-allele-carrier patients with ADHD had lower CBCL attention problems scores compared to patients with AA genotype (p = 0.023), whereas T-allele-carriers in the community sample had more attention problems (p = 0.042). Based on previous reports of lower NE levels in ADHD children and the inverted-U shape effect of NE on cognitive functions, we propose that rs28386840 (-3081) T-allele, which is associated with lower NET expression (and potentially higher synaptic NE level) would support attention processes among ADHD patients (similarly as atomoxetine increases NE levels), whereas it would hinder cortical functions in healthy children.
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Affiliation(s)
- Zsofia Nemoda
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Nora Angyal
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Zsanett Tarnok
- Vadaskert Child and Adolescent Psychiatric Clinic, Budapest, Hungary
| | - Emma Birkas
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.,Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary
| | - Emese Bognar
- Vadaskert Child and Adolescent Psychiatric Clinic, Budapest, Hungary
| | - Maria Sasvari-Szekely
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Judit Gervai
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Krisztina Lakatos
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
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Angyal N, Horvath EZ, Tarnok Z, Richman MJ, Bognar E, Lakatos K, Sasvari-Szekely M, Nemoda Z. Association analysis of norepinephrine transporter polymorphisms and methylphenidate response in ADHD patients. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:122-128. [PMID: 29374517 DOI: 10.1016/j.pnpbp.2018.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/27/2017] [Accepted: 01/17/2018] [Indexed: 10/18/2022]
Abstract
AIMS Methylphenidate (MPH) is the most frequently prescribed drug in Attention Deficit Hyperactivity Disorder (ADHD). Hitherto mostly the dopamine transporter gene has been studied in MPH-response and only a few studies analyzed the norepinephrine transporter (NET, SLC6A2) gene, although MPH is a potent inhibitor of both dopamine and norepinephrine transporters. We aimed to analyze this monoamine transporter gene in relation to ADHD per se and MPH-response in particular to gain further knowledge in ADHD pharmacogenetics using a Caucasian sample. METHODS Six single nucleotide polymorphisms (rs28386840, rs2242446, rs3785143, rs3785157, rs5569, rs7194256 SNP) were studied across the NET gene in 163 ADHD children (age: 9.3±2.6; 86.5% male) using ADHD-RS hyperactivity-impulsivity and inattention scales. For case-control analysis 486 control subjects were also genotyped. At the MPH-response analysis responders had minimum 25% decrease of ADHD-RS total score after 2months of treatment, and chi-square test compared 90 responders and 32 non-responders, whereas ANOVA was used to assess symptom improvement after the first month among the 122 ADHD patients. RESULTS The classical case-control analysis did not yield any association with ADHD diagnosis, which was supported by meta-analysis conducted on the available genetic data (combining previously published and the present studies). On the other hand, the intronic rs3785143 showed nominal association with inattention symptoms (p=0.01). The haplotype analysis supported this association, and indicated the importance of the first haploblock encompassing the intronic and 2 promoter SNPs. With MPH-response only the promoter rs28386840 showed nominal association: Those with at least one T-allele were overrepresented in the responder group (42% vs 19%, p=0.08), and they had better improvement on the hyperactivity-impulsivity scale compared to the AA genotype (p=0.04). CONCLUSION Although none of our single SNP findings remained significant after correcting for multiple testing, our results from the MPH-response analysis indicate the potential importance of promoter variants in the NET gene.
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Affiliation(s)
- Nora Angyal
- Institute of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Erzsebet Zsofia Horvath
- Institute of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Zsanett Tarnok
- Vadaskert Child and Adolescent Psychiatric Hospital, Budapest, Hungary
| | - Mara J Richman
- Department of Clinical Psychology and Addiction, Eötvös Loránd University, Budapest, Hungary
| | - Emese Bognar
- Vadaskert Child and Adolescent Psychiatric Hospital, Budapest, Hungary
| | - Krisztina Lakatos
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Maria Sasvari-Szekely
- Institute of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
| | - Zsofia Nemoda
- Institute of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary.
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Oh SY, Kim YK. Association of norepinephrine transporter gene polymorphisms in attention-deficit/hyperactivity disorder in Korean population. Prog Neuropsychopharmacol Biol Psychiatry 2016; 73:S0278-5846(16)30326-8. [PMID: 27984158 DOI: 10.1016/j.pnpbp.2016.10.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 09/25/2016] [Accepted: 10/26/2016] [Indexed: 01/08/2023]
Abstract
We investigated the association of three single nucleotide polymorphisms(SNP) of the norepinephrine transporter (NET) gene SLC6A2, T-182C (rs2242446), A-3081T (rs28386840), and G-1287A (rs5569) with the prevalence of attention-deficit/hyperactivity disorder (ADHD), its clinical severity, and other disease-related characteristics in a Korean population. The genotype, allele frequency and haplotype of 103 ADHD patients and 173 controls were analyzed for these three SNPs. All participants completed the Korean version of the ADHD Rating Scale (K-ARS). The ADHD group also completed the Korean Educational Development Institute-Wechsler Intelligence Scale for Children (KEDI-WISC) and the Continuous Performance Test (CPT) in a drug-naive state. The χ2 test and logistic regression analysis revealed no significant differences in the genotype distribution or allele frequencies of each SNP between the ADHD group and the control. In the haplotype analysis, the most common T-A-G haplotype was related to an increased risk of ADHD in females (P=0.002). There was no statistical significance between clinical features of ADHD and any specific allele of each SNP after multiple test correction except lower omission error in non-A girl carriers (GG type) of G-1287A (carrier 76.75±18.74, non-carrier 55.00±9.26, t=3.026, P=0.007, Bonferroni-corrected P=0.042). Some values related A-3081 and G-1287A showed a trend approaching the significance level when analyzed separately by gender. Even though it was not statistically meaningful after multiple test correction, G allele might have some protective effect against development of ADHD symptoms and this finding was consistent with previous studies.
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Affiliation(s)
- So-Young Oh
- Department of Psychiatry, Seoul Metropolitan Eunpyeong Hospital, Seoul, South Korea
| | - Yong-Ku Kim
- Department of Psychiatry, College of Medicine, Korea University, Seoul, South Korea.
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Eslami Amirabadi MR, Davari-Ashtiani R, Khademi M, RajeziEsfahani S, Emamalizadeh B, Movafagh A, Arabgol F, Sadr S, Darvish H, Razjouyan K. No Evidence for Association Between Norepinephrine Transporter-3081 (A/T) Polymorphism and Attention Deficit Hyperactivity Disorder in Iranian Population. IRANIAN RED CRESCENT MEDICAL JOURNAL 2015; 17:e22996. [PMID: 26421175 PMCID: PMC4584105 DOI: 10.5812/ircmj.229961v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 09/09/2014] [Accepted: 11/09/2014] [Indexed: 11/23/2022]
Abstract
Background: Attention Deficit Hyperactivity Disorder (ADHD) can lead to drastic problems for the patient and its worldwide prevalence is 5%-12%. It also has many comorbidities with other disorders, and the genetic contribution seems the most significant cause. Objectives: The current study was conducted to investigate the association between norepinephrine transporter-3081 (A/T) polymorphisms and ADHD in Iranian population. Patients and Methods: Participants were chosen from children and adolescents diagnosed with ADHD referred to Imam Hoseyn Hospital. A child and adolescent psychiatrist confirmed the diagnosis using the Kiddie-Sads-Present and Lifetime Version (K-SADS-PL) semi-structural interview. The control group was from pupils of schools in Tehran (capital city of Iran) who had no history or presence of psychiatric and medical complications. Also, a child and adolescent psychiatrist confirmed their health using the K-SADS-PL semi-structural interview. Genetic examinations were DNA distraction, Polymerase Chain Reaction (PCR), and Restricted Fragment Length Polymorphism (RFLP), which were conducted according to standard protocols. The statistical analysis was performed using chi-square and Fisher's exact test in SPSS version 21. Results: The percentages of ADHD subtypes for combined, inattentive, and hyperactive/impulsive were 72.2%, 17.2%, and 11.9%, respectively. There was no significant association between norepinephrine transporter polymorphism and ADHD (P = 0.81). Moreover, no significant relationship was found between gender [male (P = 0.92) and female (P = 0.63)] and polymorphism. No significant association was found between subtypes of ADHD [combined (P = 0.46), inattentive (P = 0.41), hyperactive/impulsive (P = 0.32)] and polymorphism SCL6A2. This lack of association can also be seen in gender in every subtype. Conclusions: The results of the study show no significant association between norepinephrine transporter polymorphism SCL6A2 and ADHD.
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Affiliation(s)
| | - Rozita Davari-Ashtiani
- Department of Psychiatry, Imam Hosein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Mojgan Khademi
- Department of Psychiatry, Imam Hosein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Sepideh RajeziEsfahani
- Behavioral Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Babak Emamalizadeh
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Abolfazl Movafagh
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Fariba Arabgol
- Department of Psychiatry, Imam Hosein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Said Sadr
- Department of Psychiatry, Imam Hosein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
| | - Hossein Darvish
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
- Corresponding Authors: Katayoon Razjoyan, Department of Psychiatry, Imam Hosein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran. Tel/Fax: +98-2123872572, E-mail: ; Hossein Darvish, Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran. Tel/Fax: +98-2123872572, E-mail:
| | - Katayoon Razjouyan
- Department of Psychiatry, Imam Hosein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran
- Corresponding Authors: Katayoon Razjoyan, Department of Psychiatry, Imam Hosein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran. Tel/Fax: +98-2123872572, E-mail: ; Hossein Darvish, Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran. Tel/Fax: +98-2123872572, E-mail:
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Hohmann S, Hohm E, Treutlein J, Blomeyer D, Jennen-Steinmetz C, Schmidt MH, Esser G, Banaschewski T, Brandeis D, Laucht M. Association of norepinephrine transporter (NET, SLC6A2) genotype with ADHD-related phenotypes: findings of a longitudinal study from birth to adolescence. Psychiatry Res 2015; 226:425-33. [PMID: 25724484 DOI: 10.1016/j.psychres.2014.12.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 12/16/2014] [Accepted: 12/18/2014] [Indexed: 10/24/2022]
Abstract
Variation in the gene encoding for the norepinephrine transporter (NET, SLC6A2) has repeatedly been linked with ADHD, although there is some inconsistency regarding the association with specific genes. The variants for which most consistent association has been found are the NET variants rs3785157 and rs28386840. Here, we tested for their association with ADHD diagnosis and ADHD-related phenotypes during development in a longitudinal German community sample. Children were followed from age 4 to age 15, using diagnostic interviews to assess ADHD. Between the ages of 8 and 15 years, the Child Behavior Checklist (CBCL) was administered to the primary caregivers. The continuous performance task (CPT) was performed at age 15. Controlling for possible confounders, we found that homozygous carriers of the major A allele of the functional promoter variant rs28386840 displayed a higher rate of ADHD lifetime diagnosis. Moreover, homozygous carriers of the minor T allele of rs3785157 were more likely to develop ADHD and showed higher scores on the CBCL externalizing behavior scales. Additionally, we found that individuals heterozygous for rs3785157 made fewer omission errors in the CPT than homozygotes. This is the first longitudinal study to report associations between specific NET variants and ADHD-related phenotypes during the course of development.
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Affiliation(s)
- Sarah Hohmann
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Erika Hohm
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Jens Treutlein
- Molecular Genetics Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Dorothea Blomeyer
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Christine Jennen-Steinmetz
- Department of Biostatistics, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Martin H Schmidt
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Günter Esser
- Department of Psychology, University of Potsdam, Potsdam, Germany
| | - Tobias Banaschewski
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Daniel Brandeis
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany; Department of Child and Adolescent Psychiatry, University of Zurich, Zurich, Switzerland
| | - Manfred Laucht
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany; Department of Psychology, University of Potsdam, Potsdam, Germany.
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Liu L, Cheng J, Li H, Yang L, Qian Q, Wang Y. The possible involvement of genetic variants of NET1 in the etiology of attention-deficit/hyperactivity disorder comorbid with oppositional defiant disorder. J Child Psychol Psychiatry 2015; 56:58-66. [PMID: 24942521 DOI: 10.1111/jcpp.12278] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/25/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) often coexist and shared some genetic influences. Evidence from the existing literature indicated that comorbid with ODD may increase the heterogeneity of ADHD genetics. Our present study sought to investigate the role of norepinephrine transporter gene (NET1) for ADHD comorbid with ODD. METHODS Six single nucleotide polymorphisms (SNPs) of NET1 were genotyped for a total of 1,815 ADHD cases, including 587 subjects (32.3%) with ODD. Chi-square tests were conducted for pseudo case-control study comparing allelic and genotypic distributions between ADHD with and without ODD. Among them, there were 1,249 probands together with their parents composing trios for family-based association studies using transmission disequilibrium tests (TDTs). In addition, 1,337 ADHD probands have detailed information of ODD symptoms and were included for quantitative analyses with genotypes using analyses of covariance (ANCOVA). To consider the overlap and correlation of other comorbidities with ODD and eliminate their potential confounding effect, we further repeated above analyses for 'pure ADHD+ODD' versus 'ADHD-only' after excluding other comorbidities except for ODD. RESULTS The pseudo case-control study showed different allelic and genotypic distributions of SNP rs3785143 between ADHD with ODD and those without ODD. Family-based association tests indicated overtransmission of the T allele of rs3785143 in ADHD with ODD trios, but no biased transmission in those without ODD. ANCOVA showed association between genotypes of rs3785143 with ODD symptoms in ADHD probands, especially with 'Argumentative/Defiant Behavior (ADB)' dimension after controlling gender, age, clinical subtypes and intelligence. Above association still existed after removing the samples with other comorbidities. CONCLUSION NET1 was associated with comorbidity of ODD and ODD symptoms in ADHD probands. Our findings emphasize the importance of considering the comorbidity of ODD in ADHD genetic studies, especially ADHD with ADB. However, further replication in independent sample or different populations is still needed.
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Affiliation(s)
- Lu Liu
- Peking University Sixth Hospital, Institute of Mental Health, Beijing, China; Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, China
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Song J, Hong HJ, Lee BO, Yook KH. Association of Norepinephrine Transporter Gene and Side Effects of Osmotic-Release Oral System Methylphenidate in Attention-Deficit Hyperactivity Disorder. Soa Chongsonyon Chongsin Uihak 2014. [DOI: 10.5765/jkacap.2014.25.2.82] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Pazvantoğlu O, Güneş S, Karabekiroğlu K, Yeğin Z, Erenkuş Z, Akbaş S, Sarısoy G, Korkmaz IZ, Böke O, Bağcı H, Sahin AR. The relationship between the presence of ADHD and certain candidate gene polymorphisms in a Turkish sample. Gene 2013; 528:320-7. [PMID: 23872233 DOI: 10.1016/j.gene.2013.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/17/2013] [Accepted: 07/02/2013] [Indexed: 01/29/2023]
Abstract
Due to the high heritability of attention-deficit hyperactivity disorder (ADHD), parents of children with ADHD appear to represent a good sample group for investigating the genetics of the disorder. The aim of this study was to investigate the association between ADHD and six polymorphisms in five candidate genes [5-HT2A (rs6311), NET1 (rs2242447), COMT (rs4818), NTF3 (rs6332), SNAP-25 (rs3746544) and (rs1051312)]. We included 228 parents of children diagnosed with ADHD and 109 healthy parents as the control group. The polymorphisms were genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) assays and analyzed using the chi-square test and the multinomial logit model. SNAP-25 (rs3746544) polymorphism was associated with loading for ADHD, while 5-HT2A (rs6311) and NET1 (rs2242447) polymorphisms were associated with ADHD. On the other hand, there was no significant association between the SNAP-25 (rs1051312), NTF3 (rs6332), or COMT (rs4818) gene polymorphisms and ADHD. In addition, we found that even if variation in the SNAP-25 gene alone does not affect the phenotype, it may nevertheless lead to the emergence of a clinical ADHD picture in the presence of other genetic factors. Our findings suggest that a combination of NET1 (rs2242447) and SNAP-25 (rs3746544) is a risk factor for ADHD. Problems associated with the noradrenergic and serotonergic systems and SNAP-25 may play a role, both alone and in interaction with one another, in the pathophysiological mechanisms of ADHD.
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Affiliation(s)
- Ozan Pazvantoğlu
- Department of Psychiatry, Ondokuz Mayis University, School of Medicine, Samsun, Turkey.
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Cain RE, Wasserman MC, Waterhouse BD, McGaughy JA. Atomoxetine facilitates attentional set shifting in adolescent rats. Dev Cogn Neurosci 2013; 1:552-9. [PMID: 21927630 DOI: 10.1016/j.dcn.2011.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Adolescent rats show immaturities in executive function and are less able than adult rats to learn reinforcement reversals and shift attentional set. These two forms of executive function rely on the functional integrity of the orbitofrontal and prelimbic cortices respectively. Drugs used to treat attention deficit disorder, such as atomoxetine, that increase cortical catecholamine levels improve executive functions in humans, non-human primates and adult rats with prefrontal lesions. Cortical noradrenergic systems are some of the last to mature in primates and rats. Moreover, norepinephrine transporters (NET) are higher in juvenile rats than adults. The underdeveloped cortical noradrenergic system and higher number of NET are hypothesized to underlie the immaturities in executive function found in adolescents. We assessed executive function in male Long-Evans rats using an intra-dimensional/extradimensional set shifting task. We administered the NET blocker, atomoxetine (0.0, 0.1, 0.9 mg/kg/ml; i.p.), prior to the test of attentional set shift and a reinforcement reversal. The lowest dose of drug facilitated attentional set shifting but had no effect on reversal learning. These data demonstrate that NET blockade allows adolescent rats to more easily perform attentional set shifting.
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Affiliation(s)
- Rachel E Cain
- University of New Hampshire, Department of Psychology, Durham, NH 03824, United States
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Thakur GA, Sengupta SM, Grizenko N, Choudhry Z, Joober R. Comprehensive phenotype/genotype analyses of the norepinephrine transporter gene (SLC6A2) in ADHD: relation to maternal smoking during pregnancy. PLoS One 2012; 7:e49616. [PMID: 23185385 PMCID: PMC3502190 DOI: 10.1371/journal.pone.0049616] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 10/11/2012] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE Despite strong pharmacological evidence implicating the norepinephrine transporter in ADHD, genetic studies have yielded largely insignificant results. We tested the association between 30 tag SNPs within the SLC6A2 gene and ADHD, with stratification based on maternal smoking during pregnancy, an environmental factor strongly associated with ADHD. METHODS Children (6-12 years old) diagnosed with ADHD according to DSM-IV criteria were comprehensively evaluated with regard to several behavioral and cognitive dimensions of ADHD as well as response to a fixed dose of methylphenidate (MPH) using a double-blind placebo controlled crossover trial. Family-based association tests (FBAT), including categorical and quantitative trait analyses, were conducted in 377 nuclear families. RESULTS A highly significant association was observed with rs36021 (and linked SNPs) in the group where mothers smoked during pregnancy. Association was noted with categorical DSM-IV ADHD diagnosis (Z=3.74, P=0.0002), behavioral assessments by parents (CBCL, P=0.00008), as well as restless-impulsive subscale scores on Conners'-teachers (P=0.006) and parents (P=0.006). In this subgroup, significant association was also observed with cognitive deficits, more specifically sustained attention, spatial working memory, planning, and response inhibition. The risk allele was associated with significant improvement of behavior as measured by research staff (Z=3.28, P=0.001), parents (Z=2.62, P=0.009), as well as evaluation in the simulated academic environment (Z=3.58, P=0.0003). CONCLUSIONS By using maternal smoking during pregnancy to index a putatively more homogeneous group of ADHD, highly significant associations were observed between tag SNPs within SLC6A2 and ADHD diagnosis, behavioral and cognitive measures relevant to ADHD and response to MPH. This comprehensive phenotype/genotype analysis may help to further understand this complex disorder and improve its treatment. Clinical trial registration information - Clinical and Pharmacogenetic Study of Attention Deficit with Hyperactivity Disorder (ADHD); www.clinicaltrials.gov; NCT00483106.
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Affiliation(s)
- Geeta A. Thakur
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
- Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | | | - Natalie Grizenko
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
- Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Zia Choudhry
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Ridha Joober
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Douglas Mental Health University Institute, Montreal, Quebec, Canada
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Park S, Kim JW, Yang YH, Hong SB, Park MH, Kim BN, Shin MS, Yoo HJ, Cho SC. Possible effect of norepinephrine transporter polymorphisms on methylphenidate-induced changes in neuropsychological function in attention-deficit hyperactivity disorder. Behav Brain Funct 2012; 8:22. [PMID: 22591463 PMCID: PMC3508798 DOI: 10.1186/1744-9081-8-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 05/16/2012] [Indexed: 11/23/2022] Open
Abstract
Background Dysregulation of noradrenergic system may play important roles in pathophysiology of attention-deficit/hyperactivity disorder (ADHD). We examined the relationship between polymorphisms in the norepinephrine transporter SLC6A2 gene and attentional performance before and after medication in children with ADHD. Methods Fifty-three medication-naïve children with ADHD were genotyped and evaluated using the continuous performance test (CPT). After 8-weeks of methylphenidate treatment, these children were evaluated by CPT again. We compared the baseline CPT measures and the post-treatment changes in the CPT measures based on the G1287A and the A-3081T polymorphisms of SLC6A2. Results There was no significant difference in the baseline CPT measures associated with the G1287A or A-3081T polymorphisms. After medication, however, ADHD subjects with the G/G genotype at the G1287A polymorphism showed a greater decrease in the mean omission error scores (p = 0.006) than subjects with the G/A or A/A genotypes, and subjects with the T allele at the A-3081T polymorphism (T/T or A/T) showed a greater decrease in the mean commission error scores (p = 0.003) than those with the A/A genotypes. Conclusions Our results provide evidence for the possible role of the G1287A and A-3081T genotypes of SLC6A2 in methylphenidate-induced improvement in attentional performance and support the noradrenergic hypothesis for the pathophysiology of ADHD.
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Affiliation(s)
- Subin Park
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
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Regional brain perfusion before and after treatment with methylphenidate may be associated with the G1287A polymorphism of the norepinephrine transporter gene in children with attention-deficit/hyperactivity disorder. Neurosci Lett 2012; 514:159-63. [DOI: 10.1016/j.neulet.2012.02.079] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 02/23/2012] [Accepted: 02/23/2012] [Indexed: 11/20/2022]
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No evidence for association between a functional promoter variant of the Norepinephrine Transporter gene SLC6A2 and ADHD in a family-based sample. ACTA ACUST UNITED AC 2011; 3:285-9. [DOI: 10.1007/s12402-011-0060-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 06/07/2011] [Indexed: 01/07/2023]
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Song DH, Jhung K, Song J, Cheon KA. The 1287 G/A polymorphism of the norepinephrine transporter gene (NET) is involved in commission errors in Korean children with attention deficit hyperactivity disorder. Behav Brain Funct 2011; 7:12. [PMID: 21569456 PMCID: PMC3104482 DOI: 10.1186/1744-9081-7-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 05/13/2011] [Indexed: 11/25/2022] Open
Abstract
Background Previous evidence supports the role of noradrenergic systems in ADHD, and norepinephrine transporter (NET) is critical in regulating the noradrenergic system. The present study aimed to investigate the association between NET gene polymorphism and the performance measures of the Continuous Performance Test (CPT) in Korean ADHD children. Methods Eighty-seven children (mean age = 9.23 ± 1.99 years) with ADHD were recruited from a university hospital. Genotypes of G1287A of the NET gene (SLC6A2) were analyzed. All participants completed the CPT, with performance measures of omission errors, commission errors, reaction time and reaction standardization computed. The relationship between G1287A polymorphisms and CPT performance measures was examined. Results There were 46 subjects with the G/G genotype, 35 subjects with the G/A genotype and 6 subjects with the A/A genotype. Among the three groups, there were no significant differences in the performance of CPTs. When dichotomized according to whether the subjects have the rare allele or not, subjects with the homozygous G/G genotype showed significantly lower commission errors compared to those without G/G genotypes (by independent T-test, t = -2.18, p = 0.026). Discussion Our study found a significant association between commission errors of the CPT and the G1287A genotype of the NET gene in Korean ADHD children. These findings suggest a protective role of the G/G genotype of the NET polymorphisms in the deficits of response inhibition in ADHD children.
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Affiliation(s)
- Dong-Ho Song
- Department of Child and Adolescent Psychiatry and Institute of Behavioral Science in Medicine, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, South Korea
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Lee SH, Kim SW, Lee MG, Yook KH, Greenhill LL, Fradin KN, Hong HJ. Lack of association between response of OROS-methylphenidate and norepinephrine transporter (SLC6A2) polymorphism in Korean ADHD. Psychiatry Res 2011; 186:338-44. [PMID: 20863575 DOI: 10.1016/j.psychres.2010.08.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 07/23/2010] [Accepted: 08/28/2010] [Indexed: 01/08/2023]
Abstract
This study investigated the relationship between the five common polymorphisms (rs2242446, rs5568, rs5569, rs998424, and rs1616905) in the norepinephrine transporter (NET) gene and the OROS-methylphenidate response in a medication-naïve Korean attention-deficit hyperactivity disorder (ADHD) sample. One hundred thirty-seven patients with ADHD were recruited from the child and adolescent psychiatric outpatient units. The trial was an eight-week, open-label study of OROS-methylphenidate monotherapy, and treatment outcomes were measured using the Korean version of the ADHD Rating Scales-IV (K-ARS) for the parents, the Clinician Global Impression Severity Scale (CGI-S) and the Clinician Global Impression Improvement Scale (CGI-I). Associations between the five NET polymorphisms and the drug response were analyzed using genotype and allele frequencies at each locus. There was no significant difference in genotype and allele distribution for each NET polymorphism between responders and non-responders (P>0.05). There were no significant differences in change of the K-ARS score, change of CGI-S scores or CGI-I scores at 8 weeks among each genotype and allele of five NET polymorphisms (P>0.05). Although there were no significant positive results, our findings may have several implications and offer direction for future studies.
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Affiliation(s)
- Sung Hee Lee
- Department of Pharmacology, Yonsei University, Seoul, Republic of Korea
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Archer T, Oscar-Berman M, Blum K. Epigenetics in Developmental Disorder: ADHD and Endophenotypes. ACTA ACUST UNITED AC 2011; 2. [PMID: 22224195 DOI: 10.4172/2157-7412.1000104] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Heterogeneity in attention-deficit/hyperactivity disorder (ADHD), with complex interactive operations of genetic and environmental factors, is expressed in a variety of disorder manifestations: severity, co-morbidities of symptoms, and the effects of genes on phenotypes. Neurodevelopmental influences of genomic imprinting have set the stage for the structural-physiological variations that modulate the cognitive, affective, and pathophysiological domains of ADHD. The relative contributions of genetic and environmental factors provide rapidly proliferating insights into the developmental trajectory of the condition, both structurally and functionally. Parent-of-origin effects seem to support the notion that genetic risks for disease process debut often interact with the social environment, i.e., the parental environment in infants and young children. The notion of endophenotypes, markers of an underlying liability to the disorder, may facilitate detection of genetic risks relative to a complex clinical disorder. Simple genetic association has proven insufficient to explain the spectrum of ADHD. At a primary level of analysis, the consideration of epigenetic regulation of brain signalling mechanisms, dopamine, serotonin, and noradrenaline is examined. Neurotrophic factors that participate in the neurogenesis, survival, and functional maintenance of brain systems, are involved in neuroplasticity alterations underlying brain disorders, and are implicated in the genetic predisposition to ADHD, but not obviously, nor in a simple or straightforward fashion. In the context of intervention, genetic linkage studies of ADHD pharmacological intervention have demonstrated that associations have fitted the "drug response phenotype," rather than the disorder diagnosis. Despite conflicting evidence for the existence, or not, of genetic associations between disorder diagnosis and genes regulating the structure and function of neurotransmitters and brain-derived neurotrophic factor (BDNF), associations between symptoms-profiles endophenotypes and single nucleotide polymorphisms appear reassuring.
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Affiliation(s)
- Trevor Archer
- Department of Psychology, University of Gothenburg, Box 500, SE-40530 Gothenburg, Sweden
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Kim BN, Kim JW, Hong SB, Cho SC, Shin MS, Yoo HJ. Possible association of norepinephrine transporter -3081(A/T) polymorphism with methylphenidate response in attention deficit hyperactivity disorder. Behav Brain Funct 2010; 6:57. [PMID: 20929549 PMCID: PMC2959002 DOI: 10.1186/1744-9081-6-57] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 10/07/2010] [Indexed: 12/25/2022] Open
Abstract
Background Attention-deficit/hyperactivity disorder (ADHD) is a heritable disorder characterized by symptoms of inattention and/or hyperactivity/impulsivity. Methylphenidate (MPH) has been shown to block the norepinephrine transporter (NET), and genetic investigations have demonstrated that the norepinephrine transporter gene (SLC6A2) is associated with ADHD. The aims of this study were to examine the association of the SLC6A2 -3081(A/T) and G1287A polymorphisms with MPH response in ADHD. Methods This study enrolled 112 children and adolescents with ADHD. A response criterion was defined based on the Clinical Global Impression-Improvement (CGI-I) score, and the ADHD Rating Scale-IV (ARS) score was also assessed at baseline and 8 weeks after MPH treatment. Results We found that the subjects who had the T allele as one of the alleles (A/T or T/T genotypes) at the -3081(A/T) polymorphism showed a better response to MPH treatment than those with the A/A genotype as measured by the CGI-I. We also found a trend towards a difference in the change of the total ARS scores and hyperactivity/impulsivity subscores between subjects with and without the T allele. No significant association was found between the genotypes of the SLC6A2 G1287A polymorphism and response to ADHD treatment. Conclusion Our findings provide evidence for the involvement of the -3081(A/T) polymorphism of SLC6A2 in the modulation of the effectiveness of MPH treatment in ADHD.
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Affiliation(s)
- Boong-Nyun Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea
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Song JE, Yook KH, Lee SH, Kim SW, Lee MG, Hong HJ. Case-Control Association Study of the Norepinephrine Transporter Gene Polymorphism in Children with ADHD. Soa Chongsonyon Chongsin Uihak 2010. [DOI: 10.5765/jkacap.2010.21.1.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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