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Tan BJW, Pang XL, Png S, Zhou ZD, Tan EK. Genetic Association Studies in Restless Legs Syndrome: Risk Variants & Ethnic Differences. Can J Neurol Sci 2024:1-16. [PMID: 38267254 DOI: 10.1017/cjn.2024.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
BACKGROUND Genetic association studies have not produced consistent results in restless legs syndrome (RLS). OBJECTIVES To conduct a systematic review on genetic association studies in RLS to highlight the common gene variants and ethnic differences. METHODOLOGY We conducted Pubmed, Embase, and Cochrane search using terms "Genetic association studies" and "restless legs syndrome" for candidate gene-based studies. Out of the initial 43 studies, 18 case control studies (from 2012 to 2022) were included. Thirteen studies including 10794 Caucasian subjects (4984 RLS cases and 5810 controls) and five studies involving 2009 Asian subjects (796 RLS cases and 1213 controls) were tabulated and analyzed. In addition, three Genome-Wide Association Studies (GWAS) in Asians and Europeans/Caucasians were included for comparisons. RESULTS In the Asian population, gene variants in BST1, SNCA Rep1, IL1B, BTBD9, and MAP2K5/SKOR1 increased the risk of RLS (odds ratio range 1.2-2.8). In Caucasian populations, examples of variants that were associated with an increased risk of RLS (odds ratio range 1.1-1.9) include those in GABRR3 TOX3, ADH1B, HMOX1, GLO1, DCDC2C, BTBD9, SKOR1, and SETBP1. Based on the meta-analysis of GWAS studies, the rs9390170 variant in UTRN gene was identified to be a novel genetic marker for RLS in Asian cohorts, whereas rs113851554 in MEIS1 gene was a strong genetic factor among the >20 identified gene variants for RLS in Caucasian populations. CONCLUSION Our systemic review demonstrates that multiple genetic variants modulate risk of RLS in Caucasians (such as MEIS1 BTBD9, MAP2K5) and in Asians (such as BTBD9, MAP2K5, and UTRN).
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Affiliation(s)
- Brendan Jen-Wei Tan
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
| | - Xin-Ler Pang
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
| | - Sarah Png
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
| | - Zhi Dong Zhou
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
- The Neuroscience and Behavioural Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
- The Neuroscience and Behavioural Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
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Jiménez-Jiménez FJ, Gómez-Tabales J, Alonso-Navarro H, Rodríguez C, Turpín-Fenoll L, Millán-Pascual J, Álvarez I, Pastor P, Calleja M, García-Ruiz R, Navarro-Muñoz S, Recio-Bermejo M, Plaza-Nieto JF, García-Albea E, García-Martín E, Agúndez JAG. LAG3/CD4 Genes Variants and the Risk for Restless Legs Syndrome. Int J Mol Sci 2022; 23:ijms232314795. [PMID: 36499121 PMCID: PMC9739762 DOI: 10.3390/ijms232314795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/08/2022] [Accepted: 11/23/2022] [Indexed: 12/02/2022] Open
Abstract
According to several studies, inflammatory factors could be related to the pathogenesis of idiopathic restless legs syndrome (RLS). In addition, RLS and Parkinson's disease (PD) have shown a possible relationship, and recent studies have shown an association between CD4 rs1922452 and CD4 rs951818 single nucleotide variants (SNVs) and the risk for PD. For these reasons, we investigated the possible association between common variants in the LAG3/CD4 genes (which encoded proteins involved in inflammatory and autoimmune responses) and the risk for RLS in a Caucasian Spanish population. We assessed the frequencies of CD4 rs1922452, CD4 rs951818, and LAG3 rs870849 genotypes and allelic variants in 285 patients with idiopathic RLS and 350 healthy controls using a specific TaqMan-based qPCR assay. We also analyzed the possible influence of the genotypes' frequencies on several variables, including age at onset of RLS, gender, family history of RLS, and response to drugs commonly used in the treatment of RLS. We found a lack of association between the frequencies of genotypes and allelic variants of the 3 SNVs studied and the risk of RLS, and a weak though significant association between the CD4 rs1922452 GG genotype and an older age at onset of RLS. With the exception of this association, our findings suggest that common SNVs in the CD4/LAG3 genes are not associated with the risk of developing idiopathic RLS in Caucasian Spanish people.
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Affiliation(s)
- Félix Javier Jiménez-Jiménez
- Section of Neurology, Hospital Universitario del Sureste, E28500 Arganda del Rey, Spain
- Correspondence: or ; Tel.: +34-636-968-395
| | - Javier Gómez-Tabales
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, E10003 Cáceres, Spain
| | | | - Christopher Rodríguez
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, E10003 Cáceres, Spain
| | - Laura Turpín-Fenoll
- Section of Neurology, Hospital La Mancha-Centro, E13600 Alcázar de San Juan, Spain
| | - Jorge Millán-Pascual
- Section of Neurology, Hospital La Mancha-Centro, E13600 Alcázar de San Juan, Spain
| | - Ignacio Álvarez
- Fundació per la Recerca Biomèdica i Social Mútua de Terrassa, E08221 Terrassa, Spain
- Movement Disorders Unit, Department of Neurology, Hospital Universitari Mutua de Terrassa, E08221 Terrassa, Spain
| | - Pau Pastor
- Fundació per la Recerca Biomèdica i Social Mútua de Terrassa, E08221 Terrassa, Spain
- Movement Disorders Unit, Department of Neurology, Hospital Universitari Mutua de Terrassa, E08221 Terrassa, Spain
- Unit of Neurodegenerative Diseases, Department of Neurology, The Germans Trias i Pujol Research Institute (IGTP), University Hospital Germans Trias i Pujol, E08916 Badalona, Spain
| | - Marisol Calleja
- Section of Neurology, Hospital Universitario del Sureste, E28500 Arganda del Rey, Spain
| | - Rafael García-Ruiz
- Section of Neurology, Hospital La Mancha-Centro, E13600 Alcázar de San Juan, Spain
| | | | - Marta Recio-Bermejo
- Section of Neurology, Hospital La Mancha-Centro, E13600 Alcázar de San Juan, Spain
| | | | - Esteban García-Albea
- Department of Medicine-Neurology, Universidad de Alcalá, E28801 Alcalá de Henares, Spain
| | - Elena García-Martín
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, E10003 Cáceres, Spain
| | - José A. G. Agúndez
- ARADyAL Instituto de Salud Carlos III, University Institute of Molecular Pathology Biomarkers, Universidad de Extremadura, E10003 Cáceres, Spain
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Schormair B, Zhao C, Salminen AV, Oexle K, Winkelmann J. Reassessment of candidate gene studies for idiopathic restless legs syndrome in a large genome-wide association study dataset of European ancestry. Sleep 2022; 45:6576194. [PMID: 35486972 PMCID: PMC9366638 DOI: 10.1093/sleep/zsac098] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/06/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
Study Objectives
Several candidate gene studies have been published for idiopathic restless legs syndrome (RLS) in populations of European ancestry, but the reported associations have not been confirmed in independent samples. Our aim was to reassess these findings in a large case–control dataset in order to evaluate their validity.
Methods
We screened PubMed for RLS candidate gene studies. We used the genome-wide association study (GWAS) dataset of the International EU-RLS-GENE Consortium as our replication sample, which provided genome-wide single-variant association data based on at most 17 220 individuals of European ancestry. We performed additional gene-based tests using the software MAGMA and assessed the power of our study using the genpwr R package.
Results
We identified 14 studies conducted in European samples which assessed 45 variants in 27 genes of which 5 variants had been reported as significantly associated. None of these individual variants were replicated in our GWAS-based reassessment (nominal p > 0.05) and gene-based tests for the respective five genes ADH1B, GABRR3, HMOX1, MAOA, and VDR, were also nonsignificant (nominal p > 0.05). Our replication dataset was well powered to detect the reported effects, even when adjusting for effect size overestimation due to winner’s curse. Power estimates were close to 100% for all variants.
Conclusion
In summary, none of the significant single-variant associations from candidate gene studies were confirmed in our GWAS dataset. Therefore, these associations were likely false positive. Our observations emphasize the need for large sample sizes and stringent significance thresholds in future association studies for RLS.
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Affiliation(s)
- Barbara Schormair
- Institute of Neurogenomics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Neuherberg , Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich , Munich , Germany
| | - Chen Zhao
- Institute of Neurogenomics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Neuherberg , Germany
| | - Aaro V Salminen
- Institute of Neurogenomics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Neuherberg , Germany
| | - Konrad Oexle
- Institute of Neurogenomics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Neuherberg , Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich , Munich , Germany
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Neuherberg , Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich , Munich , Germany
- Chair of Neurogenetics, School of Medicine, Technical University of Munich , Munich , Germany
- Munich Cluster for Systems Neurology (SyNergy) , Munich , Germany
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