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Al-Kafaji G, Jahrami HA, Alwehaidah MS, Alshammari Y, Husni M. Mitochondrial DNA copy number in autism spectrum disorder and attention deficit hyperactivity disorder: a systematic review and meta-analysis. Front Psychiatry 2023; 14:1196035. [PMID: 37484684 PMCID: PMC10361772 DOI: 10.3389/fpsyt.2023.1196035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/21/2023] [Indexed: 07/25/2023] Open
Abstract
Background Several reports suggest that altered mitochondrial DNA copy number (mtDNA-cn), a common biomarker for aberrant mitochondrial function, is implicated in autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), but the results are still elusive. Methods A meta-analysis was performed to summarize the current indication and to provide a more precise assessment of the mtDNA-cn in ASD and ADHD. A search in the MEDLINE-PubMed, Scopus, and EMBASE databases was done to identify related studies up to the end of February 2023. The meta-analysis was conducted according to recommendations of the Cochrane Handbook of Systematic Reviews. Results Fourteen studies involving 666 cases with ASD and ADHD and 585 controls were collected and judged relevant for the systematic review and meta-analysis. The pooled results by a random effects meta-analysis was reported as a geometric mean of the estimated average response ratio and 95% confidence interval. Overall analysis of studies reported differences in mtDNA-cn in blood samples (k = 10) and non-blood samples (brain tissues and oral samples; k = 4) suggested significantly higher mtDNA-cn in patients compared to controls (p = 0.0275). Sub-analysis by stratifying studies based on tissue type, showed no significant increase in mtDNA-cn in blood samples among patients and controls (p = 0.284). Conversely, higher mtDNA-cn was observed in non-blood samples in patients than in controls (p = 0.0122). Further stratified analysis based on blood-cell compositions as potential confounds showed no significant difference in mtDNA-cn in peripheral blood samples of patients comparted to controls (p = 0.074). In addition, stratified analysis of aged-matched ASD and ADHD patients and controls revealed no significant difference in mtDNA-cn in blood samples between patients and controls (p = 0.214), whereas a significant increase in mtDNA-cn was observed in non-blood samples between patients and controls (p < 0.001). Finally, when the mtDNA-cn was analyzed in blood samples of aged-matched patients with ASD (peripheral blood, leukocytes, and PBMCs) or ADHD (peripheral blood), no significant difference in mtDNA-cn was observed between ASD patients and controls (p = 0.385), while a significant increase in mtDNA-cn was found between ADHD patients and controls (p = 0.033). Conclusion In this first meta-analysis of the evaluation of mtDNA-cn in ASD/ADHD, our results show elevated mtDNA-cn in ASD and ADHD, further emphasizing the implication of mitochondrial dysfunction in neurodevelopmental disorders. However, our results indicate that the mtDNA-cn in blood is not reflected in other tissues in ASD/ADHD, and the true relationship between blood-derived mtDNA-cn and ASD/ADHD remains to be defined in future studies. The importance of blood-cell compositions as confounders of blood-based mtDNA-cn measurement and the advantages of salivary mtDNA-cn should be considered in future studies. Moreover, the potential of mtDNA-cn as a biomarker for mitochondrial malfunction in neurodevelopmental disorders deserves further investigations.
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Affiliation(s)
- Ghada Al-Kafaji
- Department of Molecular Medicine and Al-Jawhara Centre for Molecular Medicine, Genetics, and Inherited Disorders, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
| | - Haitham Ali Jahrami
- Department of Psychiatry, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
- Government Hospital, Manama, Bahrain
| | - Materah Salem Alwehaidah
- Department of Medical Laboratory, Faculty of Allied Health, Kuwait University, Kuwait City, Kuwait
| | | | - Mariwan Husni
- Department of Psychiatry, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
- Department of Psychiatry, Northern Ontarion School of Medicine University, Thunder Bay, ON, Canada
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Giannoulis SV, Müller D, Kennedy JL, Gonçalves V. Systematic review of mitochondrial genetic variation in attention-deficit/hyperactivity disorder. Eur Child Adolesc Psychiatry 2022:10.1007/s00787-022-02030-6. [PMID: 35796884 DOI: 10.1007/s00787-022-02030-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 06/20/2022] [Indexed: 11/03/2022]
Abstract
The global prevalence of attention-deficit/hyperactivity disorder (ADHD) is estimated to be between 6% and 7% in children worldwide. The pathophysiology of this heterogeneous neurodevelopmental disorder remains unknown. Mitochondrial dysfunction has been proposed as a possible contributing factor to the etiology of ADHD. There is limited literature available to help our understanding of this hypothesis, and thus we conducted a systematic review of the number and quality of studies pertaining to mitochondrial genetic alterations in ADHD. A systematic search was conducted in the relevant databases Medline (PubMed) and Embase up to March 2021. Inclusion criteria included randomized control trials, cross-sectional studies, and case-control studies. This search resulted in a total of 507 articles that emerged from the search criteria. Of these results, 10 primary research articles were selected for in depth review based on the inclusion and exclusion criteria. These studies all reported on mitochondrial genetic variation in ADHD cases such as increased copy number, single-nucleotide polymorphisms, and haplogroup associations. This initial review of the experimental literature suggests mitochondrial genetic variation, in both the mitochondrial DNA and nuclear-encoded mitochondrial genes, may indeed contribute to ADHD pathophysiology. The studies reviewed here provide promising evidence for future research to further examine the mitochondrial genetics contributing to ADHD pathophysiology. We suggest that expansion of investigations into mitochondrial mechanisms may have potential to inform new treatment options for ADHD.
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Affiliation(s)
- Stavroula V Giannoulis
- Molecular Brain Science Research Department, Tannenbaum Centre for Pharmacogenetics, Centre for Addiction and Mental Health, Neurogenetics Section, Campbell Family Mental Health Research Institute, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Daniel Müller
- Molecular Brain Science Research Department, Tannenbaum Centre for Pharmacogenetics, Centre for Addiction and Mental Health, Neurogenetics Section, Campbell Family Mental Health Research Institute, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - James L Kennedy
- Molecular Brain Science Research Department, Tannenbaum Centre for Pharmacogenetics, Centre for Addiction and Mental Health, Neurogenetics Section, Campbell Family Mental Health Research Institute, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Vanessa Gonçalves
- Molecular Brain Science Research Department, Tannenbaum Centre for Pharmacogenetics, Centre for Addiction and Mental Health, Neurogenetics Section, Campbell Family Mental Health Research Institute, 250 College Street, Toronto, ON, M5T 1R8, Canada.
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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Khoury NM, Radonjić NV, Albert AB, Faraone SV. From Structural Disparities to Neuropharmacology: A Review of Adult Attention-Deficit/Hyperactivity Disorder Medication Treatment. Child Adolesc Psychiatr Clin N Am 2022; 31:343-361. [PMID: 35697389 DOI: 10.1016/j.chc.2022.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Adult attention-deficit/hyperactivity disorder (ADHD) is an early-onset disorder with many functional impairments and psychiatric comorbidities. Although no treatment fully mitigates impairments associated with ADHD, effective management is possible with pharmacologic and nonpharmacologic treatments. The etiology and pathophysiology of ADHD are remarkably complex and the disorder is continuously distributed in the population. While these findings have been well documented in studies with predominantly white samples, ADHD may affect racial and ethnic minorities differentially, given diagnostic and treatment disparities. This review provides an updated overview of the epidemiology, etiology, neurobiology, and neuropharmacology of ADHD, addressing racial and ethnic disparities whereby data are available.
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Affiliation(s)
- Nayla M Khoury
- Department of Psychiatry and Behavioral Sciences, Upstate Medical University, Syracuse, NY, USA
| | - Nevena V Radonjić
- Department of Psychiatry and Behavioral Sciences, Upstate Medical University, Syracuse, NY, USA
| | - Avery B Albert
- Clinical Psychology, Syracuse University, Syracuse, NY, USA
| | - Stephen V Faraone
- Department of Psychiatry and Behavioral Science, SUNY Upstate Medical University, Institute for Human Performance, Room 3707, 505 Irving Avenue, Syracuse, NY 13210, USA; Department of Neuroscience and Physiology, SUNY Upstate Medical University, Institute for Human Performance, Room 3707, 505 Irving Avenue, Syracuse, NY 13210, USA.
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