1
|
Ansari MA, Naqvi HA, Khidri FF, Rajput AH, Mahmood A, Waryah AM. Gene-gene and gene-environmental interaction of dopaminergic system genes in Pakistani children with attention deficit hyperactivity disorder. Saudi J Biol Sci 2024; 31:104045. [PMID: 39050560 PMCID: PMC11268355 DOI: 10.1016/j.sjbs.2024.104045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 06/07/2024] [Accepted: 06/07/2024] [Indexed: 07/27/2024] Open
Abstract
Background Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder influenced by genetic and environmental factors. This study examined the specific gene variants, dopamine transporter 1 (DAT1) rs6350, dopamine receptor D3 (DRD3) rs6280, dopamine receptor D2 (DRD2) rs6277, and catechol-O-methyltransferase (COMT) rs4633, in relation to ADHD among Pakistani children by exploring the potential gene-gene and gene-environment interactions. Methods A total of 100 cases of ADHD and 100 healthy children were recruited. The tetra-primer amplification refractory mutation system (ARMS) assays were designed for genotyping the selected variants in both groups, and their association with ADHD was determined in different genetic models. Gene-gene and gene-environmental interactions were determined by the multifactor dimensionality reduction (MDR) method. Results The DAT1 rs6350 SNV AA genotype showed a significantly increased risk for ADHD in the codominant and recessive models. Conversely, the AG genotype demonstrated a protective factor for ADHD in the codominant and overdominant models. The DRD3 rs6280 T allele exhibited a decreased risk for ADHD, and the TT genotype showed a reduced risk in the recessive and log-additive models. No association between the DRD2 rs6277 and COMT rs4633 SNVs with ADHD was found in our population. The MDR analysis of the best three-fold interaction model showed redundancy between DAT1 rs6350 and DRD3 rs6280; however, the risk was increased with the gender variable, which showed a weak synergistic interaction with these SNVs. Conclusion Genes associated with dopaminergic neurotransmission may contribute to the occurrence of ADHD. Furthermore, gene-gene and gene-environmental interactions may increase ADHD susceptibility.
Collapse
Affiliation(s)
- Moin Ahmed Ansari
- Institute of Biotechnology and Genetic Engineering, University of Sindh, Jamshoro, Pakistan
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
- Department of Psychiatry, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Habib Ahmed Naqvi
- Institute of Biotechnology and Genetic Engineering, University of Sindh, Jamshoro, Pakistan
| | - Feriha Fatima Khidri
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
- Department of Biochemistry, Bilawal Medical College, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Aatir Hanif Rajput
- Department of Psychiatry, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Ambar Mahmood
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Ali Muhammad Waryah
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| |
Collapse
|
2
|
Caputi V, Hill L, Figueiredo M, Popov J, Hartung E, Margolis KG, Baskaran K, Joharapurkar P, Moshkovich M, Pai N. Functional contribution of the intestinal microbiome in autism spectrum disorder, attention deficit hyperactivity disorder, and Rett syndrome: a systematic review of pediatric and adult studies. Front Neurosci 2024; 18:1341656. [PMID: 38516317 PMCID: PMC10954784 DOI: 10.3389/fnins.2024.1341656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/02/2024] [Indexed: 03/23/2024] Open
Abstract
Introduction Critical phases of neurodevelopment and gut microbiota diversification occur in early life and both processes are impacted by genetic and environmental factors. Recent studies have shown the presence of gut microbiota alterations in neurodevelopmental disorders. Here we performed a systematic review of alterations of the intestinal microbiota composition and function in pediatric and adult patients affected by autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Rett syndrome (RETT). Methods We searched selected keywords in the online databases of PubMed, Cochrane, and OVID (January 1980 to December 2021) with secondary review of references of eligible articles. Two reviewers independently performed critical appraisals on the included articles using the Critical Appraisal Skills Program for each study design. Results Our systematic review identified 18, 7, and 3 original articles describing intestinal microbiota profiles in ASD, ADHD, and RETT, respectively. Decreased Firmicutes and increased Bacteroidetes were observed in the gut microbiota of individuals affected by ASD and ADHD. Proinflammatory cytokines, short-chain fatty acids and neurotransmitter levels were altered in ASD and RETT. Constipation and visceral pain were related to changes in the gut microbiota in patients affected by ASD and RETT. Hyperactivity and impulsivity were negatively correlated with Faecalibacterium (phylum Firmicutes) and positively correlated with Bacteroides sp. (phylum Bacteroidetes) in ADHD subjects. Five studies explored microbiota-or diet-targeted interventions in ASD and ADHD. Probiotic treatments with Lactobacillus sp. and fecal microbiota transplantation from healthy donors reduced constipation and ameliorated ASD symptoms in affected children. Perinatal administration of Lactobacillus sp. prevented the onset of Asperger and ADHD symptoms in adolescence. Micronutrient supplementation improved disease symptomatology in ADHD without causing significant changes in microbiota communities' composition. Discussion Several discrepancies were found among the included studies, primarily due to sample size, variations in dietary practices, and a high prevalence of functional gastrointestinal symptoms. Further studies employing longitudinal study designs, larger sample sizes and multi-omics technologies are warranted to identify the functional contribution of the intestinal microbiota in developmental trajectories of the human brain and neurobehavior. Systematic review registration https://clinicaltrials.gov/, CRD42020158734.
Collapse
Affiliation(s)
- Valentina Caputi
- Poultry Production and Product Safety Research Unit, Agricultural Research Service, United States Department of Agriculture, Fayetteville, AR, United States
| | - Lee Hill
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Department of Pediatrics, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Melanie Figueiredo
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Jelena Popov
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Harvard Medical School, Boston, MA, United States
- Boston Children’s Hospital, Boston, MA, United States
| | - Emily Hartung
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Department of Biochemistry and Biomedical Sciences, Faculty of Science, McMaster University, Hamilton, ON, Canada
| | - Kara Gross Margolis
- Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, United States
- New York University Pain Research Center, New York, NY, United States
- New York University College of Dentistry, New York, NY, United States
| | - Kanish Baskaran
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Papiha Joharapurkar
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Michal Moshkovich
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Nikhil Pai
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Division of Gastroenterology, Hepatology and Nutrition, McMaster Children’s Hospital, Hamilton, ON, Canada
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
- Division of Gastroenterology, Hepatology, and Nutrition, the Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| |
Collapse
|
3
|
Zhong L, He H, Zhang J, Gao X, Yin F, Zuo P, Song R. Gene Interaction of Dopaminergic Synaptic Pathway Genes in Attention-Deficit Hyperactivity Disorder: a Case-Control Study in Chinese Children. Mol Neurobiol 2024; 61:42-54. [PMID: 37578679 PMCID: PMC10791714 DOI: 10.1007/s12035-023-03523-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 07/19/2023] [Indexed: 08/15/2023]
Abstract
Attention-deficit hyperactivity disorder is a highly inherited neurodevelopmental disorder. Previous genetic research has linked ADHD to certain genes in the dopaminergic synaptic pathway. Nonetheless, research on this relationship has produced varying results across various populations. China is a multi-ethnic country with its own unique genetic characteristics. Therefore, such a population can provide useful information about the relationship between gene polymorphisms in dopaminergic synaptic pathways and ADHD. This study looked at the genetic profiles of 284 children in China's Xinjiang. In total, 142 ADHD children and 142 control subjects were enrolled. Following the extraction of DNA from oral mucosal cells, 13 SNPs for three candidate genes (SLC6A3, DRD2, and GRIN2B) in the dopaminergic synaptic pathway of ADHD were screened. Based on the results of single nucleotide polymorphism (SNP) analyses, we found that the DRD2 gene variants rs6277 and rs6275, and the SLC6A3 gene variant rs2652511, were significantly associated with ADHD in boys and girls, respectively, after adjusting for false discovery rate (FDR) in terms of allele frequencies. Furthermore, our generalized multifactorial downscaling approach identified a significant association between rs6275 and rs1012586. These findings suggest that DRD2 and SLC6A3 genes have a crucial role in ADHD susceptibility. Additionally, we observed that the interaction between GRIN2B and DRD2 genes may contribute to the susceptibility of Chinese children with ADHD.
Collapse
Affiliation(s)
- Lin Zhong
- Medical College of Shihezi University, Xinjiang, Shihezi, 832000, China
| | - Hongyao He
- Medical College of Shihezi University, Xinjiang, Shihezi, 832000, China
| | - Jing Zhang
- Medical College of Shihezi University, Xinjiang, Shihezi, 832000, China
| | - Xiaoyan Gao
- Medical College of Shihezi University, Xinjiang, Shihezi, 832000, China
| | - Feifei Yin
- Medical College of Shihezi University, Xinjiang, Shihezi, 832000, China
| | - Pengxiang Zuo
- Medical College of Shihezi University, Xinjiang, Shihezi, 832000, China.
| | - Ranran Song
- Department of Maternal and Child Health and MOE Key Lab of Environment and Health, School of Public Health, Huazhong University of Science and Technology, Wuhan, 430000, China.
| |
Collapse
|
4
|
Xiong Z, Yan J, Shi S. Val158Met polymorphisms of COMT gene and serum concentrations of catecholaminergic neurotransmitters of ADHD in Chinese children and adolescents. Medicine (Baltimore) 2021; 100:e27867. [PMID: 34889236 PMCID: PMC8663844 DOI: 10.1097/md.0000000000027867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 10/19/2021] [Accepted: 11/03/2021] [Indexed: 01/05/2023] Open
Abstract
ABSTRACT This study analyzed the Val158Met polymorphisms of the catechol-O-methyltransferase (COMT) gene and serum concentrations of catecholaminergic neurotransmitters in attention deficit hyperactivity disorder (ADHD) children and adolescents.All the subjects (180 paired ADHD and non-ADHD children and adolescents) were genotyped for the Val158Met polymorphisms of the COMT gene, and determined by the difference of dopamine and noradrenalin from a 1:1 paired case-control study.The frequencies of methionine (A)/A, valine (G)/A, and G/G were 51.67%, 41.11%, and 7.22% in the case group, and 62.22%, 31.11%, and 6.67% in the control group. There was a significant difference in the distribution of all genotypes of the COMT gene between the 2 groups (odds ratio = 1.85, 95% confidence interval: 1.62-2.08; χ2 = 7.80, P < .05). The serum concentrations of dopamine and noradrenalin were 1.42 ± 0.34 ng/mL and 177.70 ± 37.92 pg/mL in the case group, and 1.94 ± 0.42 ng/mL and 206.20 ± 42.45 pg/mL in the control group. There were the significant differences in the levels of dopamine and noradrenalin between the 2 groups (dopamine: t = 4.30, P < .01; noradrenalin: t = 2.24, P < .05).Our study suggested that the Val158Met polymorphisms of the COMT gene and serum concentrations of catecholaminergic neurotransmitters were associated with ADHD children and adolescents.
Collapse
Affiliation(s)
- Zhonggui Xiong
- Department of Child Health, Maternal and Child Health Hospital of Hubei Province, Wuhan, China
| | - Jiong Yan
- Department of Child Health, Maternal and Child Health Hospital of Hubei Province, Wuhan, China
| | - Shuhua Shi
- Department of Maternal and Child Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
5
|
DRD4 48 bp multiallelic variants as age-population-specific biomarkers in attention-deficit/hyperactivity disorder. Transl Psychiatry 2020; 10:70. [PMID: 32075956 PMCID: PMC7031506 DOI: 10.1038/s41398-020-0755-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 12/10/2019] [Accepted: 12/20/2019] [Indexed: 01/09/2023] Open
Abstract
The identification of biomarkers to support the diagnosis and prediction of treatment response for attention-deficit/hyperactivity disorder (ADHD) is still a challenge. Our previous works highlighted the DRD4 (dopamine receptor D4) as the best potential genetic marker for childhood diagnosis and methylphenidate (MPH) response. Here, we aimed to provide additional evidence on biomarkers for ADHD diagnosis and treatment response, by using more specific approaches such as meta-analytic and bioinformatics tools. Via meta-analytic approaches including over 3000 cases and 16,000 controls, we demonstrated that, among the different variants studied in DRD4 gene, the 48-base pair, Variable Tandem Repeat Polymorphism, VNTR in exon 3 showed an age/population-specificity and an allelic heterogeneity. In particular, the 7R/"long" allele was identified as an ADHD risk factor in European-Caucasian populations (d = 1.31, 95%CI: 1.17-1.47, Z = 4.70/d = 1.36, 95%CI: 1.20-1.55, Z = 4.78, respectively), also, from the results of last meta-analysis, linked to the poor MPH efficacy. The 4R/"short" allele was a protective factor in European-Caucasian and South American populations (d = 0.83, 95%CI: 0.75-0.92, Z = 3.58), and was also associated to positive MPH response. These results refer to children with ADHD. No evidence of such associations was detected for adults with persistent ADHD (data from the last meta-analysis). Moreover, we found evidence that the 4R allele leads to higher receptor expression and increased sensitivity to dopamine, as compared with the 7R allele (d = 1.20, 95%CI: 0.71-1.69, Z = 4.81), and this is consistent with the ADHD protection/susceptibility effects of the respective alleles. Using bioinformatics tools, based on the latest genome-wide association (GWAS) meta-analysis of the Psychiatry Genomic Consortium (PGC), we demonstrated that the 48 bp VNTR is not in Linkage Disequilibrium with the DRD4 SNPs (Single Nucleotide Polymorphisms), which were not found to be associated with ADHD. Moreover, a DRD4 expression downregulation was found in ADHD specific brain regions (Putamen, Z score = -3.02, P = 0.00252). Overall, our results suggest that DRD4 48 bp VNTR variants should be considered as biomarkers to support the diagnosis of ADHD and to predict MPH response, although the accuracy of such a biomarker remains to be further elucidated.
Collapse
|
6
|
Blum K, Gondré-Lewis MC, Baron D, Thanos PK, Braverman ER, Neary J, Elman I, Badgaiyan RD. Introducing Precision Addiction Management of Reward Deficiency Syndrome, the Construct That Underpins All Addictive Behaviors. Front Psychiatry 2018; 9:548. [PMID: 30542299 PMCID: PMC6277779 DOI: 10.3389/fpsyt.2018.00548] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 10/12/2018] [Indexed: 12/21/2022] Open
Affiliation(s)
- Kenneth Blum
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, United States.,Department of Psychiatry, Boonshoft School of Medicine, Dayton VA Medical Center, Wright State University, Dayton, OH, United States.,University of Vermont College of Medicine, Burlington, VM, United States.,Division of Addictive Services, Dominion Diagnostics, LLC, North Kingston, RI, United States.,Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Institute of Psychology, University of Eötvös Loránd, Budapest, Hungary.,Department of Clinical Neurology, Path Foundation, New York, NY, United States.,Division of Neuroscience and Addiction Therapy, Summit Estate Recovery Center, Los Gatos, CA, United States.,Department of Neurogenetics Research and Addiction Therapy, The Florida House Experience, Deerfield Beach, FL, United States.,National Human Genome Center, Howard University, Washington, DC, United States
| | - Marjorie C Gondré-Lewis
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Department of Anatomy, Howard University College of Medicine, Washington, DC, United States.,Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical and Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - David Baron
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, United States.,Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States
| | - Panayotis K Thanos
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical and Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States.,Department of Psychology, University at Buffalo, Buffalo, NY, United States
| | - Eric R Braverman
- Department of Clinical Neurology, Path Foundation, New York, NY, United States
| | - Jennifer Neary
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States
| | - Igor Elman
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Department of Psychiatry, Cooper Medical School of Rowan University, Camden, NJ, United States
| | - Rajendra D Badgaiyan
- Division of Precision Addiction Management, Geneus Health, LLC, San Antonio, TX, United States.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| |
Collapse
|
7
|
Kuppili PP, Manohar H, Pattanayak RD, Sagar R, Bharadwaj B, Kandasamy P. ADHD research in India: A narrative review. Asian J Psychiatr 2017; 30:11-25. [PMID: 28709018 DOI: 10.1016/j.ajp.2017.07.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 07/03/2017] [Accepted: 07/04/2017] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with no clear etiopathogenesis. Owing to unique socio cultural milieu of India, it is worthwhile reviewing research on ADHD from India and comparing findings with global research. Thereby, we attempted to provide a comprehensive overview of research on ADHD from India. METHODS A boolean search of articles published in English from September 1966 to January 2017 on electronic search engines Google Scholar, PubMed, IndMED, MedIND, using the search terms "ADHD", "Attention Deficit and Hyperactivity Disorder", "Hyperactivity" ,"Child psychiatry", "Hyperkinetic disorder", "Attention Deficit Disorder", "India"was carried out and peer - reviewed studies conducted among human subjects in India were included for review. Case reports, animal studies, previous reviews were excluded from the current review. RESULTS Results of 73 studies found eligible for the review were organized into broad themes such as epidemiology, etiology, course and follow up, clinical profile and comorbidity, assessment /biomarkers, intervention/treatment parameters, pathways to care and knowledge and attitude towards ADHD. DISCUSSION There was a gap noted in research from India in the domains of biomarkers, course and follow up and non-pharmacological intervention. The prevalence of ADHD as well as comorbidity of Bipolar Disorder was comparatively lower compared to western studies. The studies found unique to India include comparing the effect of allopathic intervention with Ayurvedic intervention, yoga as a non pharmacological intervention. There is a need for studies from India on biomarkers, studies with prospective research design, larger sample size and with matched controls.
Collapse
Affiliation(s)
- Pooja Patnaik Kuppili
- Department of Psychiatry, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry 605006, India.
| | - Harshini Manohar
- Department of Psychiatry, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry 605006, India.
| | - Raman Deep Pattanayak
- Room No. 4091, Department of Psychiatry, 4th Floor Academic Block, All India Institute of Medical Sciences (AIIMS), Ansari Nagar, New Delhi 110029, India.
| | - Rajesh Sagar
- Department of Psychiatry, 4th Floor Academic Block, All India Institute of Medical Sciences (AIIMS), Ansari Nagar, New Delhi 110029, India.
| | - Balaji Bharadwaj
- Department of Psychiatry, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry, India.
| | - Preeti Kandasamy
- Department of Psychiatry, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry, India.
| |
Collapse
|
8
|
Attention-deficit hyperactivity disorder in adults: A systematic review and meta-analysis of genetic, pharmacogenetic and biochemical studies. Mol Psychiatry 2016; 21:872-84. [PMID: 27217152 PMCID: PMC5414093 DOI: 10.1038/mp.2016.74] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/09/2016] [Accepted: 04/01/2016] [Indexed: 01/16/2023]
Abstract
The adult form of attention-deficit/hyperactivity disorder has a prevalence of up to 5% and is the most severe long-term outcome of this common disorder. Family studies in clinical samples as well as twin studies suggest a familial liability and consequently different genes were investigated in association studies. Pharmacotherapy with methylphenidate (MPH) seems to be the first-line treatment of choice in adults with attention-deficit hyperactive disorder (ADHD) and some studies were conducted on the genes influencing the response to this drug. Finally some peripheral biomarkers were identified in ADHD adult patients. We believe this work is the first systematic review and meta-analysis of candidate gene association studies, pharmacogenetic and biochemical (metabolomics) studies performed in adults with ADHD to identify potential genetic, predictive and peripheral markers linked specifically to ADHD in adults. After screening 5129 records, we selected 87 studies of which 61 were available for candidate gene association studies, 5 for pharmacogenetics and 21 for biochemical studies. Of these, 15 genetic, 2 pharmacogenetic and 6 biochemical studies were included in the meta-analyses. We obtained an association between adult ADHD and the gene BAIAP2 (brain-specific angiogenesis inhibitor 1-associated protein 2), even after Bonferroni correction, with any heterogeneity in effect size and no publication bias. If we did not apply the Bonferroni correction, a trend was found for the carriers allele 9R of dopamine transporter SLC6A3 40 bp variable tandem repeat polymorphism (VNTR) and for 6/6 homozygotes of SLC6A3 30 bp VNTR. Negative results were obtained for the 9-6 haplotype, the dopamine receptor DRD4 48 bp VNTR, and the enzyme COMT SNP rs4680. Concerning pharmacogenetic studies, no association was found for the SLC6A3 40 bp and response to MPH with only two studies selected. For the metabolomics studies, no differences between ADHD adults and controls were found for salivary cortisol, whereas lower serum docosahexaenoic acid (DHA) levels were found in ADHD adults. This last association was significant even after Bonferroni correction and in absence of heterogeneity. Other polyunsaturated fatty acids (PUFAs) such as AA (arachidonic acid), EPA (eicosapentaenoic acid) and DyLA (dihomogammalinolenic acid) levels were not different between patients and controls. No publication biases were observed for these markers. Genes linked to dopaminergic, serotoninergic and noradrenergic signaling, metabolism (DBH, TPH1, TPH2, DDC, MAOA, MAOB, BCHE and TH), neurodevelopment (BDNF and others), the SNARE system and other forty genes/proteins related to different pathways were not meta-analyzed due to insufficient data. In conclusion, we found that there were not enough genetic, pharmacogenetic and biochemical studies of ADHD in adults and that more investigations are needed. Moreover we confirmed a significant role of BAIAP2 and DHA in the etiology of ADHD exclusively in adults. Future research should be focused on the replication of these findings and to assess their specificity for ADHD.
Collapse
|
9
|
Potential contribution of dopaminergic gene variants in ADHD core traits and co-morbidity: a study on eastern Indian probands. Cell Mol Neurobiol 2014; 34:549-64. [PMID: 24585059 DOI: 10.1007/s10571-014-0038-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 02/20/2014] [Indexed: 10/25/2022]
Abstract
Association of dopaminergic genes, mainly receptors and transporters, with Attention Deficit Hyperactivity Disorder (ADHD) has been investigated throughout the world due to the importance of dopamine (DA) in various physiological functions including attention, cognition and motor activity, traits. However, till date, etiology of ADHD remains unknown. We explored association of functional variants in the DA receptor 2 (rs1799732 and rs6278), receptor 4 (exon 3 VNTR and rs914655), and transporter (rs28363170 and rs3836790) with hyperactivity, cognitive deficit, and co-morbid disorders in eastern Indian probands. Diagnostic and Statistical Manual for Mental Disorders-IV was followed for recruitment of nuclear families with ADHD probands (N = 160) and ethnically matched controls (N = 160). Cognitive deficit and hyperactive traits were measured using Conner's parents/teachers rating scale. Peripheral blood was collected after obtaining informed written consent and used for genomic DNA isolation. Genetic polymorphisms were analyzed by PCR-based methods followed by population- as well as family-based statistical analyses. Association between genotypes and cognitive/hyperactivity traits and co-morbidities was analyzed by the Multifactor dimensionality reduction (MDR) software. Case-control analysis showed statistically significant difference for rs6278 and rs28363170 (P = 0.004 and 1.332e-007 respectively) while family-based analysis exhibited preferential paternal transmission of rs28363170 '9R' allele (P = 0.04). MDR analyses revealed independent effects of rs1799732, rs6278, rs914655, and rs3836790 in ADHD. Significant independent effects of different sites on cognitive/hyperactivity traits and co-morbid disorders were also noticed. It can be summarized from the present investigation that these gene variants may influence cognitive/hyperactive traits, thereby affecting the disease etiology and associated co-morbid features.
Collapse
|