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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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Khachatryan SG, Ferri R, Fulda S, Garcia-Borreguero D, Manconi M, Muntean ML, Stefani A. Restless legs syndrome: Over 50 years of European contribution. J Sleep Res 2022; 31:e13632. [PMID: 35808955 PMCID: PMC9542244 DOI: 10.1111/jsr.13632] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.
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Affiliation(s)
- Samson G Khachatryan
- Department of Neurology and Neurosurgery, National Institute of Health, Yerevan, Armenia.,Sleep Disorders Center, Somnus Neurology Clinic, Yerevan, Armenia
| | | | - Stephany Fulda
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, Ospedale Civico, Lugano, Switzerland
| | | | - Mauro Manconi
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, Ospedale Civico, Lugano, Switzerland.,Department of Neurology, University Hospital, Inselspital, Bern, Switzerland
| | - Maria-Lucia Muntean
- Center for Parkinson's Disease and Movement Disorders, Paracelsus-Elena Klinik, Kassel, Germany
| | - Ambra Stefani
- Sleep Disorders Clinic, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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Champion D, Bui M, Aouad P, Sarraf S, Donnelly T, Bott A, Chapman C, Goh S, Ng G, Jaaniste T, Hopper J. Contrasting painless and painful phenotypes of pediatric restless legs syndrome: a twin family study. Sleep Med 2020; 75:361-367. [DOI: 10.1016/j.sleep.2020.08.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/17/2020] [Accepted: 08/21/2020] [Indexed: 01/08/2023]
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Morais MA, Franco B, Holanda ASS, Simino LADP, Manconi M, Torsoni A, Esteves AM. PTPRD as a candidate druggable target for therapies for restless legs syndrome? J Sleep Res 2020; 30:e13216. [PMID: 33111449 DOI: 10.1111/jsr.13216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 09/15/2020] [Accepted: 09/22/2020] [Indexed: 12/18/2022]
Abstract
The gene that encodes the protein tyrosine phosphatase D (PTPRD) may be related to brain circuits associated with sleep, and has been seen as an interesting molecule, a "druggable" drug target. This gene is a potential candidate for increasing therapeutic advances in restless legs syndrome, a sleep-related movement disorder, that manifests as an uncontrollable desire to move limbs (legs) to relieve uncomfortable sensations. Changes in the PTPRD gene expression may increase the chance of developing this syndrome. Treatment with pramipexole is used in restless legs syndrome. This study aims to verify the effect of treatment with pramipexole on the PTPRD expression, as well as on the sleep pattern in an animal model for restless legs syndrome. For this, an animal model of sleep-related movement disorders (spontaneously hypertensive rats) was distributed in groups: (a) spontaneously hypertensive rats-control; (b) spontaneously hypertensive rats-pramipexole (0.125 mg kg-1 for 4 weeks). The analyses of PTPRD gene and protein expression were performed in the striatum and spinal cord by quantitative real-time polymerase chain reaction and indirect enzyme-linked immunosorbent assay, respectively. Electrocorticographic and electromyographic analyses were performed. There was no difference in the PTPRD mRNA levels, as well as in the protein levels, although a tendency has been observed for decreased gene expression in the striatum and increased protein expression in the spinal cord in the spontaneously hypertensive rats-pramipexole group. Pramipexole improved the animals' sleep pattern. Thus, the treatment with pramipexole in the evaluated dose and time tended to alter the expression of the PTPRD protein in the spinal cord, in addition to significantly improving the sleep pattern.
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Affiliation(s)
- Milca A Morais
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | - Beatriz Franco
- Faculdade de Educação Física, Universidade Estadual de Campinas, Campinas, Brazil
| | | | | | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano (EOC), Lugano, Switzerland
| | - Adriana Torsoni
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | - Andrea M Esteves
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
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Why Are Women Prone to Restless Legs Syndrome? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17010368. [PMID: 31935805 PMCID: PMC6981604 DOI: 10.3390/ijerph17010368] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/29/2019] [Accepted: 12/31/2019] [Indexed: 12/17/2022]
Abstract
Restless legs syndrome is a relatively common neurologic disorder considerably more prevalent in women than in men. It is characterized by an inactivity-induced, mostly nocturnal, uncomfortable sensation in the legs and an urge to move them to make the disagreeable sensation disappear. Some known genes contribute to this disorder and the same genes contribute to an overlapping condition—periodic leg movements that occur during sleep and result in insomnia. Dopamine and glutamate transmission in the central nervous system are involved in the pathophysiology, and an iron deficiency has been shown in region-specific areas of the brain. A review of the literature shows that pregnant women are at particular risk and that increased parity is a predisposing factor. Paradoxically, menopause increases the prevalence and severity of symptoms. This implies a complex role for reproductive hormones. It suggests that changes rather than absolute levels of estrogen may be responsible for the initiation of symptoms. Both iron (at relatively low levels in women) and estrogen (at relatively high oscillating levels in women) influence dopamine and glutamate transmission, which may help to explain women’s vulnerability to this condition. The syndrome is comorbid with several disorders (such as migraine, depression, and anxiety) to which women are particularly prone. This implies that the comorbid condition or its treatment, or both, contribute to the much higher prevalence in women than in men of restless legs syndrome.
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Fu X, Wang J, Du J, Sun J, Baranova A, Zhang F. BDNF Gene's Role in Schizophrenia: From Risk Allele to Methylation Implications. Front Psychiatry 2020; 11:564277. [PMID: 33384622 PMCID: PMC7769935 DOI: 10.3389/fpsyt.2020.564277] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/25/2020] [Indexed: 11/24/2022] Open
Abstract
Background: Schizophrenia (SZ) is a severe chronic mental disorder with complex genetic mechanisms. Brain-derived neurotrophic factor (BDNF) is one of promising candidate genes for SZ, and rs6265 is a non-synonymous single nucleotide polymorphism (SNP) in BDNF. Methods: In this study, we performed a case-control association study of rs6265 in a cohort of Han Chinese population from eastern China, including 1,407 SZ patients and 1,136 healthy controls; and carried out a cis-mQTL (Methylation Quantitative Trait Loci) analysis for BDNF rs6265. Results: We found a positive association of rs6265 with SZ (P = 0.037), with the minor allele (A) of rs6265 conferring a protecting effect for SZ (OR = 0.89). Furthermore, cis-mQTL analysis indicates that rs6265 is associated with several methylation loci surrounding BDNF. Conclusions: Together, our findings provide further evidence to support the involvement of BDNF gene in the genesis of SZ.
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Affiliation(s)
- Xiaoqian Fu
- Department of Clinical Psychology, Suzhou Guangji Hospital, The Affiliated Guangji Hospital of Soochow University, Suzhou, China
| | - Jun Wang
- Department of Psychiatry, Wuxi Mental Health Center of Nanjing Medical University, Wuxi, China
| | - Jianbin Du
- Department of Psychiatry, Wuxi Mental Health Center of Nanjing Medical University, Wuxi, China
| | - Jing Sun
- Department of Psychiatry, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China
| | - Ancha Baranova
- School of Systems Biology, George Mason University, Fairfax, VA, United States.,Research Centre for Medical Genetics, Moscow, Russia
| | - Fuquan Zhang
- Department of Psychiatry, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China.,Institute of Neuropsychiatry, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China
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