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Abstract
Restless leg syndrome/Willis-Ekbom disease has brain iron deficiency that produces excessive dopamine and known genetic risks, some of which contribute to the brain iron deficiency. Dopamine treatments work temporarily but may eventually produce further postsynaptic down-regulation and worse restless leg syndrome. This article includes sections focused on pathophysiologic findings from each of these areas: genetics, cortical-spinal excitability, and iron and dopamine.
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Affiliation(s)
- Richard P Allen
- Department of Neurology, Johns Hopkins University, Asthma & Allergy Building, 1B76b, 5501 Hopkins Bayview Boulevard, Baltimore, MD 21224, USA.
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152
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Simakajornboon N, Dye TJ, Walters AS. Restless Legs Syndrome/Willis-Ekbom Disease and Growing Pains in Children and Adolescents. Sleep Med Clin 2015; 10:311-22, xiv. [PMID: 26329441 DOI: 10.1016/j.jsmc.2015.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Recent studies have shown that restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) are common in pediatric population. The diagnostic criteria for Pediatric RLS have recently been updated to simplify and integrate with newly revised adult RLS criteria. Management of RLS and PLMD involves pharmacologic and nonpharmacologic interventions. Children with low iron storage are likely to benefit from iron therapy. Although, there is limited information on pharmacologic therapy, there are emerging literatures showing the effectiveness of dopaminergic medications in the management of RLS and PLMD in children. This article covers clinical evaluation of RLS and PLMD in children and the relationship with growing pains.
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Affiliation(s)
| | - Thomas J Dye
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Arthur S Walters
- Department of Neurology, Vanderbilt University, Nashville, TN, USA
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153
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Donelson NC, Sanyal S. Use of Drosophila in the investigation of sleep disorders. Exp Neurol 2015; 274:72-9. [PMID: 26160555 DOI: 10.1016/j.expneurol.2015.06.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 06/26/2015] [Accepted: 06/30/2015] [Indexed: 12/24/2022]
Abstract
Genetic underpinnings for sleep disorders in humans remain poorly identified, investigated and understood. This is due to the inherent complexity of sleep and a disruption of normal sleep parameters in a number of neurological disorders. On the other hand, there have been steady and remarkable developments in the investigation of sleep using model organisms such as Drosophila. These studies have illuminated conserved genetic pathways, neural circuits and intra-cellular signaling modules in the regulation of sleep. Additionally, work in model systems is beginning to clarify the role of the circadian clock and basal sleep need in this process. There have also been initial efforts to directly model sleep disorders in flies in a few instances where a genetic basis has been suspected. Here, we discuss the opportunities and limitations of studying sleep disorders in Drosophila and propose that a greater convergence of basic sleep research in model organisms and human genetics should catalyze better understanding of sleep disorders and generate viable therapeutic options.
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Affiliation(s)
- Nathan C Donelson
- Neurology Research, 115 Broadway, Bio 6 Building, Biogen, Cambridge, MA 02142, USA
| | - Subhabrata Sanyal
- Neurology Research, 115 Broadway, Bio 6 Building, Biogen, Cambridge, MA 02142, USA.
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154
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Abstract
Restless legs syndrome (RLS) is a common sensorimotor trait defined by symptoms that interfere with sleep onset and maintenance in a clinically meaningful way. Nonvolitional myoclonus while awake and asleep is a sign of the disorder and an informative endophenotype. The genetic contributions to RLS/periodic leg movements are substantial, are among the most robust defined to date for a common disease, and account for much of the variance in disease expressivity. The disorder is polygenic, as revealed by recent genome-wide association studies. Experimental studies are revealing mechanistic details of how these common variants might influence RLS expressivity.
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Affiliation(s)
- David B Rye
- Program in Sleep, Department of Neurology, Emory University School of Medicine, 12 Executive Park Drive Northeast, Atlanta, GA 30329, USA.
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155
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Wong JC, Li W, Gao X. Restless Legs Syndrome as a Prognostic Tool for Cardiovascular Disease. Sleep 2015; 38:995-6. [PMID: 26085294 DOI: 10.5665/sleep.4790] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 05/26/2015] [Indexed: 11/03/2022] Open
Affiliation(s)
- Janice C Wong
- Department of Neurology, Brigham and Women's Hospital; Department of Neurology, Massachusetts General Hospital; Harvard Medical School, Boston, MA
| | - Weijuan Li
- Department of Medicine, Albert Einstein College of Medicine
| | - Xiang Gao
- Department of Nutritional Health, Pennsylvania State University, University Park, PA
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156
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Koo BB. Restless Leg Syndrome Across the Globe: Epidemiology of the Restless Legs Syndrome/Willis-Ekbom Disease. Sleep Med Clin 2015; 10:189-205, xi. [PMID: 26329429 DOI: 10.1016/j.jsmc.2015.05.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
There are more than 50 epidemiologic studies measuring the prevalence of restless legs syndrome/Willis-Ekbom disease (RLS/WED) across 5 of the 6 inhabited continents (not Australia), most conducted in North America and Europe. Sufficient studies have been conducted in Asia, North America, and Europe to make inferences on RLS/WED prevalence by region. RLS/WED prevalence is thought to be highest in North America and Europe and lower in Asia. These differences across regions may be explained by cultural, environmental, and genetic factors. Future investigation is needed to determine to what extent these factors affect expression of RLS/WED according to world region.
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Affiliation(s)
- Brian B Koo
- Department of Neurology, Yale University School of Medicine, 15 York Street, New Haven, CT 06510, USA; Department of Neurology, West Haven VAMC, Connecticut Veterans Affairs Healthcare System, 950 Campbell Avenue, West Haven, CT 06516, USA.
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157
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Garcia-Borreguero D, Benitez A, Kohnen R, Allen R. Augmentation of restless leg syndrome (Willis-Ekbom disease) during long-term dopaminergic treatment. Postgrad Med 2015; 127:716-25. [PMID: 26077324 DOI: 10.1080/00325481.2015.1058140] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is a common sensorimotor disorder that can generally be effectively managed in the primary care clinic. However, some treatment complications may arise. According to the recommendations of the International Restless Legs Syndrome Study Group, non-ergot dopamine-receptor agonists have over the past years been one of the first-line treatments for patients with RLS/WED requiring pharmacological therapy. Augmentation is the main complication of long-term dopaminergic treatment of RLS/WED and is defined as an overall worsening of symptoms beyond pretreatment levels in patients who experienced an initial positive therapeutic response. Once identified on the basis of its characteristic clinical features, augmentation requires careful management. In order to provide clinicians with a comprehensive understanding of this common treatment complication, this review discusses the clinical features of augmentation, and its differentiation from morning rebound, symptom fluctuations and natural disease progression. Reported incidences of augmentation in clinical trials of dopaminergic RLS/WED therapies are summarized. Finally, the hypothetical pathophysiology of augmentation and the current recommendations for management of patients with augmented RLS/WED symptoms are discussed.
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158
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Abstract
Many current pharmacological treatments for neuropsychiatric disorders, such as anxiety and depression, are limited by a delayed onset of therapeutic effect, adverse side effects, abuse potential or lack of efficacy in many patients. These off-target effects highlight the need to identify novel mechanisms and targets for treatment. Recently, modulation of Glo1 (glyoxalase I) activity was shown to regulate anxiety-like behaviour and seizure-susceptibility in mice. These effects are likely to be mediated through the regulation of MG (methylglyoxal) by Glo1, as MG acts as a competitive partial agonist at GABA(A) (γ-aminobutyric acid A) receptors. Thus modulation of MG by Glo1 represents a novel target for treatment. In the present article, we evaluate the therapeutic potential of indirectly modulating MG concentrations through Glo1 inhibitors for the treatment of neuropsychiatric disorders.
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159
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Abstract
Restless legs syndrome is a common sensorimotor disorder characterized by an urge to move, and associated with uncomfortable sensations in the legs (limbs). Restless legs syndrome can lead to sleep-onset or sleep-maintenance insomnia, and occasionally excessive daytime sleepiness, all leading to significant morbidity. Brain iron deficiency and dopaminergic neurotransmission abnormalities play a central role in the pathogenesis of this disorder, along with other nondopaminergic systems, although the exact mechanisms are still. Intensive care unit patients are especially vulnerable to have unmasking or exacerbation of restless legs syndrome because of sleep deprivation, circadian rhythm disturbance, immobilization, iron deficiency, and use of multiple medications that can antagonize dopamine.
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Affiliation(s)
- Saiprakash B Venkateshiah
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Octavian C Ioachimescu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA.
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160
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161
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Upper limb function is normal in patients with restless legs syndrome (Willis-Ekbom Disease). Clin Neurophysiol 2015; 126:736-42. [DOI: 10.1016/j.clinph.2014.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 06/27/2014] [Accepted: 07/07/2014] [Indexed: 11/21/2022]
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162
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Kang SG, Lee HJ, Lee SH, Kim L. MEIS1, a Promising Candidate Gene, Is Not Associated with the Core Symptoms of Antipsychotic-Induced Restless Legs Syndrome in Korean Schizophrenia Patients. Psychiatry Investig 2015; 12:263-7. [PMID: 25866529 PMCID: PMC4390599 DOI: 10.4306/pi.2015.12.2.263] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/10/2014] [Accepted: 12/23/2014] [Indexed: 01/14/2023] Open
Abstract
OBJECTIVE Restless legs syndrome (RLS) is a distressing sleep disorder to which individuals appear to be genetically predisposed. In the present study, we assumed that antipsychotic-induced RLS symptoms were attributable to differences in individual genetic susceptibility, and investigated whether MEIS1, a promising candidate gene, was associated with antipsychotic-induced RLS symptoms in schizophrenia patients. METHODS All subjects were diagnosed with schizophrenia by board-certified psychiatrists using the Korean version of the Structured Clinical Interview for DSM-IV. We assessed antipsychotic-induced RLS symptoms in 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group. Genotyping was performed for the rs2300478 and rs6710341 polymorphisms of the MEIS1 gene. RESULTS We divided subjects into RLS symptom (n=96) and non-symptom (n=94) groups. There was no significant between-group difference in the genotype or allele frequencies of the two polymorphisms investigated, nor in the frequency of the rs2300478-rs6710341 haplotype. CONCLUSION Our data do not suggest that the rs2300478 and rs6710341 polymorphisms of the MEIS1 gene are associated with the core symptoms of antipsychotic-induced RLS in schizophrenia; different genetic mechanisms may underlie antipsychotic-induced vs. primary RLS.
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Affiliation(s)
- Seung-Gul Kang
- Department of Psychiatry, Gil Medical Center, Gachon University School of Medicine, Incheon, Republic of Korea
| | - Heon-Jeong Lee
- Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea
| | - Seung-Hwan Lee
- Department of Psychiatry, Inje University College of Medicine, Goyang, Republic of Korea
| | - Leen Kim
- Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea
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163
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Budhiraja R, Siddiqi TA, Quan SF. Sleep disorders in chronic obstructive pulmonary disease: etiology, impact, and management. J Clin Sleep Med 2015; 11:259-70. [PMID: 25700872 DOI: 10.5664/jcsm.4540] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 12/21/2014] [Indexed: 01/18/2023]
Abstract
ABSTRACT Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality and may frequently be complicated by sleep disorders. Insomnia and obstructive sleep apnea are commonly encountered in patients with COPD. Nocturnal hypoxemia is also prevalent in COPD may occur despite adequate awake oxygenation and can be especially severe in rapid eye movement sleep. Additionally, several factors--some of them unique to COPD--can contribute to sleep-related hypoventilation. Recognition of hypoventilation can be vital as supplemental oxygen therapy itself can acutely worsen hypoventilation and lead to disastrous consequences. Finally, accruing data establish an association between restless leg syndrome and COPD--an association that may be driven by hypoxemia and/or hypercapnia. Comorbid sleep disorders portend worse sleep quality, diminished quality of life, and multifarious other adverse consequences. The awareness and knowledge regarding sleep comorbidities in COPD has continued to evolve over past many years. There are still several lacunae, however, in our understanding of the etiologies, impact, and therapies of sleep disorders, specifically in patients with COPD. This review summarizes the latest concepts in prevalence, pathogenesis, diagnosis, and management of diverse sleep disorders in COPD.
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Affiliation(s)
- Rohit Budhiraja
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Tufts Medical Center, Boston, MA
| | - Tauseef A Siddiqi
- Division of Allergy, Critical Care, Pulmonary and Sleep Medicine, Department of Medicine, University of Arizona College of Medicine, Tucson, AZ
| | - Stuart F Quan
- Division of Allergy, Critical Care, Pulmonary and Sleep Medicine, Department of Medicine, University of Arizona College of Medicine, Tucson, AZ.,Divisions of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
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164
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165
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Bogan RK, Cheray JA. Restless Legs Syndrome: A Review of Diagnosis and Management in Primary Care. Postgrad Med 2015; 125:99-111. [DOI: 10.3810/pgm.2013.05.2636] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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166
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Wijemanne S, Jankovic J. Restless legs syndrome: clinical presentation diagnosis and treatment. Sleep Med 2015; 16:678-90. [PMID: 25979181 DOI: 10.1016/j.sleep.2015.03.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 02/28/2015] [Accepted: 03/02/2015] [Indexed: 12/27/2022]
Abstract
Restless legs syndrome (RLS) is a circadian disorder of sensory-motor integration that may be related to genetically determined dysregulation of iron transport across the blood-brain barrier. Dopamine agonists (DAs) have been considered the first-line therapy, but with the growing appreciation of problems associated with long-term treatment, particularly augmentation and impulse control disorder, alpha-2-delta drugs, such as gabapentin, are now considered the first line of treatment in patients with troublesome RLS. Opioids can be considered as an alternative therapy, particularly in patients with DA-related augmentation. In more severe cases, a combination therapy may be required. Intravenous iron therapy may be considered on those patients with refractory RLS.
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Affiliation(s)
- Subhashie Wijemanne
- Parkinson's Disease Center and Movement Disorders Clinic, Baylor College of Medicine, Houston, Texas, USA
| | - Joseph Jankovic
- Parkinson's Disease Center and Movement Disorders Clinic, Baylor College of Medicine, Houston, Texas, USA.
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167
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An update on restless legs syndrome (Willis-Ekbom disease): clinical features, pathogenesis and treatment. Curr Opin Neurol 2015; 27:493-501. [PMID: 24978636 DOI: 10.1097/wco.0000000000000117] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE OF REVIEW In recent years, there have been a number of advances in the field of restless legs syndrome (RLS) or Willis-Ekbom disease (WED). Here, we review recent studies pertaining to the diagnosis and clinical features, pathogenesis, and treatment of RLS/WED. RECENT FINDINGS Recent studies have added a temporal dimension to RLS/WED epidemiology by examining both the incidence and persistence rates in different populations. Diagnostic criteria have been modified to increase sensitivity, and new guidelines take into account recently published studies of different drug classes. SUMMARY Recent epidemiological findings have shown that RLS/WED is a common neurological disorder that affects up to 5% of the adult population in Western countries. In moderate and severe cases, RLS/WED has a strong impact on sleep and quality of life and can involve an increased cardiovascular risk. Diagnosis is made clinically by confirming the presence of the five essential criteria. However, in difficult cases objective tests such as the multiple suggested immobilization test (m-SIT) can be used. The pathophysiology is partially known, with several risk polymorphisms (BTBD-9 (BTB (POZ) domain containing 9), MEIS-1 (Meis homeobox 1), protein tyrosine phosphatase, receptor type, D, and others) playing an important role, along with dopaminergic and iron dysfunctions. The disorder frequently requires long-term treatment with low-dose dopamine agonists or α2δ ligands. Dopamine agonists are usually effective but the main complication, RLS/WED augmentation, can arise.
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168
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Liu C, Chung M. Genetics and epigenetics of circadian rhythms and their potential roles in neuropsychiatric disorders. Neurosci Bull 2015; 31:141-59. [PMID: 25652815 DOI: 10.1007/s12264-014-1495-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/19/2015] [Indexed: 01/07/2023] Open
Abstract
Circadian rhythm alterations have been implicated in multiple neuropsychiatric disorders, particularly those of sleep, addiction, anxiety, and mood. Circadian rhythms are known to be maintained by a set of classic clock genes that form complex mutual and self-regulatory loops. While many other genes showing rhythmic expression have been identified by genome-wide studies, their roles in circadian regulation remain largely unknown. In attempts to directly connect circadian rhythms with neuropsychiatric disorders, genetic studies have identified gene mutations associated with several rare sleep disorders or sleep-related traits. Other than that, genetic studies of circadian genes in psychiatric disorders have had limited success. As an important mediator of environmental factors and regulators of circadian rhythms, the epigenetic system may hold the key to the etiology or pathology of psychiatric disorders, their subtypes or endophenotypes. Epigenomic regulation of the circadian system and the related changes have not been thoroughly explored in the context of neuropsychiatric disorders. We argue for systematic investigation of the circadian system, particularly epigenetic regulation, and its involvement in neuropsychiatric disorders to improve our understanding of human behavior and disease etiology.
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Affiliation(s)
- Chunyu Liu
- State Key Laboratory of Medical Genetics of China, Changsha, 410078, China,
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169
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Kripke DF, Kline LE, Nievergelt CM, Murray SS, Shadan FF, Dawson A, Poceta JS, Cronin J, Jamil SM, Tranah GJ, Loving RT, Grizas AP, Hahn EK. Genetic variants associated with sleep disorders. Sleep Med 2015; 16:217-24. [PMID: 25660813 PMCID: PMC4352103 DOI: 10.1016/j.sleep.2014.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/30/2014] [Accepted: 11/14/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The diagnostic boundaries of sleep disorders are under considerable debate. The main sleep disorders are partly heritable; therefore, defining heritable pathophysiologic mechanisms could delineate diagnoses and suggest treatment. We collected clinical data and DNA from consenting patients scheduled to undergo clinical polysomnograms, to expand our understanding of the polymorphisms associated with the phenotypes of particular sleep disorders. METHODS Patients at least 21 years of age were recruited to contribute research questionnaires, and to provide access to their medical records, saliva for deoxyribonucleic acid (DNA), and polysomnographic data. From these complex data, 38 partly overlapping phenotypes were derived indicating complaints, subjective and objective sleep timing, and polysomnographic disturbances. A custom chip was used to genotype 768 single-nucleotide polymorphisms (SNPs). Additional assays derived ancestry-informative markers (eg, 751 participants of European ancestry). Linear regressions controlling for age, gender, and ancestry were used to assess the associations of each phenotype with each of the SNPs, highlighting those with Bonferroni-corrected significance. RESULTS In peroxisome proliferator-activated receptor gamma, coactivator 1 beta (PPARGC1B), rs6888451 was associated with several markers of obstructive sleep apnea. In aryl hydrocarbon receptor nuclear translocator-like (ARNTL), rs10766071 was associated with decreased polysomnographic sleep duration. The association of rs3923809 in BTBD9 with periodic limb movements in sleep was confirmed. SNPs in casein kinase 1 delta (CSNK1D rs11552085), cryptochrome 1 (CRY1 rs4964515), and retinoic acid receptor-related orphan receptor A (RORA rs11071547) were less persuasively associated with sleep latency and time of falling asleep. CONCLUSIONS SNPs associated with several sleep phenotypes were suggested, but due to risks of false discovery, independent replications are needed before the importance of these associations can be assessed, followed by investigation of molecular mechanisms.
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Affiliation(s)
- Daniel F Kripke
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
| | | | | | - Sarah S Murray
- Department of Pathology, Center for Advanced Laboratory Medicine, University of California, San Diego, CA, USA
| | - Farhad F Shadan
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA
| | - Arthur Dawson
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA
| | - J Steven Poceta
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA
| | - John Cronin
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA
| | - Shazia M Jamil
- Viterbi Family Sleep Center, Scripps Clinic, La Jolla, CA, USA
| | - Gregory J Tranah
- California Pacific Medical Center Research Institute, San Francisco, CA, USA
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170
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Tan MS, Jiang T, Tan L, Yu JT. Genome-wide association studies in neurology. ANNALS OF TRANSLATIONAL MEDICINE 2015; 2:124. [PMID: 25568877 DOI: 10.3978/j.issn.2305-5839.2014.11.12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 03/04/2013] [Indexed: 12/11/2022]
Abstract
Genome-wide association studies (GWAS) are a powerful tool for understanding the genetic underpinnings of human disease. In this article, we briefly review the role and findings of GWAS in common neurological diseases, including Stroke, Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis, migraine, amyotrophic lateral sclerosis, frontotemporal lobar degeneration, restless legs syndrome, intracranial aneurysm, human prion diseases and moyamoya disease. We then discuss the present and future implications of these findings with regards to disease prediction, uncovering basic biology, and the development of potential therapeutic agents.
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Affiliation(s)
- Meng-Shan Tan
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
| | - Teng Jiang
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
| | - Lan Tan
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
| | - Jin-Tai Yu
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
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171
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Koo BB. Restless Legs Syndrome: Would You Like That with Movements or Without? Tremor Other Hyperkinet Mov (N Y) 2015; 5:316. [PMID: 26175956 PMCID: PMC4499805 DOI: 10.7916/d80p0z0h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 04/30/2015] [Indexed: 04/24/2023] Open
Abstract
The restless legs syndrome (RLS) is a common sensorimotor condition that often results in discomfort and sleep disturbance. Diagnosis of RLS is entirely clinical and based upon a patient's description of subjective symptoms, and thus when considering RLS diagnosis non-specificity is a real problem. RLS is associated with periodic limb movements during sleep (PLMS) in up to 90% of RLS sufferers; however, their presence is neither sufficient nor necessary for the diagnosis of RLS. The disease RLS and the motor phenomenon of PLMS share similarities in various areas, which include pathophysiology, pharmacology, genetics, and epidemiology. The purpose of this opinion piece is to outline the many similarities between RLS and PLMS in order to make an argument for the inclusion of PLMS as a supplementary diagnostic criterion of RLS, termed electro-clinical RLS, which would consist of the current clinical RLS diagnosis plus PLMS. This additional criterion could be used in cases where diagnosis is unclear to increase specificity or in research projects where proper diagnosis is desired at the investigational level.
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Affiliation(s)
- Brian B. Koo
- Department of Neurology, VA Connecticut Healthcare System, West Haven, Connecticut, USA
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
- To whom correspondence should be addressed. E-mail:
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172
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Veauthier C, Gaede G, Radbruch H, Sieb JP, Wernecke KD, Paul F. Periodic limb movements during REM sleep in multiple sclerosis: a previously undescribed entity. Neuropsychiatr Dis Treat 2015; 11:2323-9. [PMID: 26396516 PMCID: PMC4574879 DOI: 10.2147/ndt.s83350] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND There are few studies describing periodic limb movement syndrome (PLMS) in rapid eye movement (REM) sleep in patients with narcolepsy, restless legs syndrome, REM sleep behavior disorder, and spinal cord injury, and to a lesser extent, in insomnia patients and healthy controls, but no published cases in multiple sclerosis (MS). The aim of this study was to investigate PLMS in REM sleep in MS and to analyze whether it is associated with age, sex, disability, and laboratory findings. METHODS From a study of MS patients originally published in 2011, we retrospectively analyzed periodic limb movements (PLMs) during REM sleep by classifying patients into two subgroups: PLM during REM sleep greater than or equal to ten per hour of REM sleep (n=7) vs less than ten per hour of REM sleep (n=59). A univariate analysis between PLM and disability, age, sex, laboratory findings, and polysomnographic data was performed. RESULTS MS patients with more than ten PLMs per hour of REM sleep showed a significantly higher disability measured by the Kurtzke expanded disability status scale (EDSS) (P=0.023). The presence of more than ten PLMs per hour of REM sleep was associated with a greater likelihood of disability (odds ratio 22.1; 95% confidence interval 3.5-139.7; P<0.0001), whereas there were no differences in laboratory and other polysomnographic findings. CONCLUSION PLMs during REM sleep were not described in MS earlier, and they are associated with disability measured by the EDSS.
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Affiliation(s)
- Christian Veauthier
- Interdisciplinary Center of Sleep Medicine, Charité University Medicine Berlin, Germany
| | - Gunnar Gaede
- NeuroCure Clinical Research Center, Charité University Medicine Berlin, Germany ; Department of Neurology, St Joseph Hospital Berlin-Weissensee, Berlin, Germany
| | - Helena Radbruch
- NeuroCure Clinical Research Center, Charité University Medicine Berlin, Germany
| | - Joern-Peter Sieb
- Department of Neurology, HELIOS Hanseklinikum Stralsund, Stralsund, Germany ; Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Klaus-Dieter Wernecke
- CRO SOSTANA GmbH, Berlin, Germany ; Institute of Medical Biometry, Charité University Medicine Berlin, Berlin, Germany
| | - Friedemann Paul
- NeuroCure Clinical Research Center, Charité University Medicine Berlin, Germany ; Clinical and Experimental Multiple Sclerosis Research Center, Department of Neurology, Charité University Medicine Berlin, Berlin, Germany
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Allen RP. History of Restless Legs Syndrome, Recently Named Willis–Ekbom Disease. Sleep Med 2015. [DOI: 10.1007/978-1-4939-2089-1_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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175
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Freeman AA, Dai H, Sanyal S. Use of Drosophila to Study Restless Legs Syndrome. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00078-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Schulte EC, Winkelmann J. Clinical Phenotype and Genetics of Restless Legs Syndrome. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00076-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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The CC genotype of the delta-sarcoglycan gene polymorphism rs13170573 is associated with obstructive sleep apnea in the Chinese population. PLoS One 2014; 9:e114160. [PMID: 25474115 PMCID: PMC4256229 DOI: 10.1371/journal.pone.0114160] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/04/2014] [Indexed: 02/05/2023] Open
Abstract
Obstructive sleep apnea (OSA) is a highly heterogeneous sleep disorder, and increasing evidence suggests that genetic factors play a role in the etiology of OSA. Airway muscle dysfunction might promote pharyngeal collapsibility, mutations or single nucleotide polymorphisms (SNPs) in the delta-sarcoglycan (SCGD) gene associated with muscle dysfunction. To evaluate if SCGD gene SNPs are associated with OSA, 101 individuals without OSA and 97 OSA patients were recruited randomly. The genotype distributions of SNPs (rs157350, rs7715464, rs32076, rs13170573 and rs1835919) in case and control populations were evaluated. The GG, GC and CC genotypes of rs13170573 in control and OSA groups were 51.5% and 37.1%, 36.6% and 35.1%, and 11.9% and 27.8%, respectively. Significantly fewer OSA patients possessed the GG genotype and significantly more possessed the CC genotype compared with controls. Further multivariate logistic regression analysis showed that the CC genotype was an independent risk factor for OSA, with an odds ratio (OR) of 2.17 (95% confidence interval [CI]: 1.19-6.01). Other factors, such as age ≥ 50 years, male gender, body mass index (BMI) ≥ 25 kg/m(2), low-density lipoprotein cholesterol (LDL-C) level ≥ 3.33 mg/dL, smoking and hypertension, were also independent risk factors for OSA in our multivariate logistic regression model.
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179
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Dissection of genetic factors associated with amyotrophic lateral sclerosis. Exp Neurol 2014; 262 Pt B:91-101. [DOI: 10.1016/j.expneurol.2014.04.013] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 03/31/2014] [Accepted: 04/14/2014] [Indexed: 12/11/2022]
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Rist PM, Tzourio C, Elbaz A, Soumaré A, Dufouil C, Mazoyer B, Kurth T. Structural brain lesions and restless legs syndrome: a cross-sectional population-based study. BMJ Open 2014; 4:e005938. [PMID: 25421338 PMCID: PMC4244423 DOI: 10.1136/bmjopen-2014-005938] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVE To evaluate the association between white matter lesion (WML) volume, silent infarcts and restless legs syndrome (RLS) in a population-based study of elderly individuals. DESIGN Cross-sectional study. SETTING Population-based Three-City study. PARTICIPANTS 1035 individuals from the Dijon, France, centre of the Three-City study who had available information on volume of WMLs from MRIs and who answered questions about the prevalence of RLS. PRIMARY OUTCOME MEASURE Prevalence of RLS. RESULTS WML volume was measured using an automated tissue segmentation method. Logistic regression was used to evaluate adjusted associations between tertiles of WML volume and RLS and between silent infarcts and RLS. 218 individuals (21.1%) were determined to have RLS. Compared with those in the first tertile of WML volume, individuals in the second tertile (OR=1.09; 95% CI 0.75 to 1.60) or third tertile (OR=1.17; 95% CI 0.79 to 1.74) did not have an increased prevalence of RLS. We also did not observe associations between the volume of deep or periventricular WML and RLS; nor did we observe an association between silent brain infarcts and RLS (OR=0.74; 95% CI 0.40 to 1.39). These findings were not modified by age or gender. CONCLUSIONS Higher volume of WML and the presence of silent infarcts were not associated with an increased prevalence of RLS in this population-based cohort of elderly individuals.
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Affiliation(s)
- Pamela M Rist
- Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Department of Epidemiology,Harvard School of Public Health, Boston, Massachusetts, USA
| | - Christophe Tzourio
- INSERM Research Center for Epidemiology and Biostatistics (U897) Team Neuroepidemiology, Bordeaux, France
- College of Health Sciences, University of Bordeaux, Bordeaux, France
| | - Alexis Elbaz
- Social and Occupational Determinants of Health, INSERM, Centre for Research in Epidemiology and Population Health, U1018, Villejuif, France
- Université de Versailles St-Quentin, Versailles, France
| | - Aïcha Soumaré
- INSERM Research Center for Epidemiology and Biostatistics (U897) Team Neuroepidemiology, Bordeaux, France
| | - Carole Dufouil
- INSERM Research Center for Epidemiology and Biostatistics (U897) Team Neuroepidemiology, Bordeaux, France
- College of Health Sciences, University of Bordeaux, Bordeaux, France
| | - Bernard Mazoyer
- College of Health Sciences, University of Bordeaux, Bordeaux, France
- CNRS CEA (UMR5296) Neurofunctional Imaging Group, University of Bordeaux, Bordeaux, France
| | - Tobias Kurth
- Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Department of Epidemiology,Harvard School of Public Health, Boston, Massachusetts, USA
- INSERM Research Center for Epidemiology and Biostatistics (U897) Team Neuroepidemiology, Bordeaux, France
- College of Health Sciences, University of Bordeaux, Bordeaux, France
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181
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González-Lázaro M, Roselló-Díez A, Delgado I, Carramolino L, Sanguino MA, Giovinazzo G, Torres M. Two new targeted alleles for the comprehensive analysis ofMeis1functions in the mouse. Genesis 2014; 52:967-75. [DOI: 10.1002/dvg.22833] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/27/2014] [Accepted: 10/27/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Mónica González-Lázaro
- Department of Cardiovascular Development and Repair; Centro Nacional de Investigaciones Cardiovasculares, CNIC; Madrid Spain
| | - Alberto Roselló-Díez
- Department of Cardiovascular Development and Repair; Centro Nacional de Investigaciones Cardiovasculares, CNIC; Madrid Spain
| | - Irene Delgado
- Department of Cardiovascular Development and Repair; Centro Nacional de Investigaciones Cardiovasculares, CNIC; Madrid Spain
| | - Laura Carramolino
- Department of Cardiovascular Development and Repair; Centro Nacional de Investigaciones Cardiovasculares, CNIC; Madrid Spain
| | - María Angeles Sanguino
- Pluripotent Cell Technology Unit; Centro Nacional de Investigaciones Cardiovasculares, CNIC; Madrid Spain
| | - Giovanna Giovinazzo
- Pluripotent Cell Technology Unit; Centro Nacional de Investigaciones Cardiovasculares, CNIC; Madrid Spain
| | - Miguel Torres
- Department of Cardiovascular Development and Repair; Centro Nacional de Investigaciones Cardiovasculares, CNIC; Madrid Spain
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182
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Alam G, Jones BC. Toxicogenetics: in search of host susceptibility to environmental toxicants. Front Genet 2014; 5:327. [PMID: 25295052 PMCID: PMC4170107 DOI: 10.3389/fgene.2014.00327] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 09/02/2014] [Indexed: 01/02/2023] Open
Abstract
Heavy metals, various pesticide and herbicides are implicated as risk factors for human health. Paraquat, maneb, and rotenone, carbamate, and organophosphorous insecticides are examples of toxicants for which acute and chronic exposure are associated with multiple neurological disorders including Parkinson’s disease. Nevertheless, the role of pesticide exposure in neurodegenerative diseases is not clear-cut, as there are inconsistencies in both the epidemiological and preclinical research. The aim of this short review is to show that at least, some of the inconsistencies are related to individual differences in susceptibility to the effects of neurotoxicants, individual differences that can be traced to the genetic constitution of the individuals and animals studies, i.e., host-based susceptibility.
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Affiliation(s)
- Gelareh Alam
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA USA
| | - Byron C Jones
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA USA
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183
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184
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Zhao M, Geng T, Qiao L, Zhang M, Shi J, Huang F, Lin X, Wang J, Zuo H. Olanzapine-induced restless legs syndrome. J Clin Neurosci 2014; 21:1622-5. [DOI: 10.1016/j.jocn.2014.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/23/2013] [Accepted: 01/09/2014] [Indexed: 10/25/2022]
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185
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Moore H, Winkelmann J, Lin L, Finn L, Peppard P, Mignot E. Periodic leg movements during sleep are associated with polymorphisms in BTBD9, TOX3/BC034767, MEIS1, MAP2K5/SKOR1, and PTPRD. Sleep 2014; 37:1535-42. [PMID: 25142570 PMCID: PMC4153066 DOI: 10.5665/sleep.4006] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES To examine association between periodic leg movements (PLM) and 13 single nucleotide polymorphisms (SNPs) in 6 loci known to increase risk of restless legs syndrome (RLS). SETTING Stanford Center for Sleep Sciences and Medicine and Clinical Research Unit of University of Wisconsin Institute for Clinical and Translational Research. PATIENTS Adult participants (n = 1,090, mean age = 59.7 years) from the Wisconsin Sleep Cohort (2,394 observations, 2000-2012). DESIGN AND INTERVENTIONS A previously validated automatic detector was used to measure PLMI. Thirteen SNPs within BTBD9, TOX3/BC034767, MEIS1 (2 unlinked loci), MAP2K5/SKOR1, and PTPRD were tested. Analyses were performed using a linear model and by PLM category using a 15 PLM/h cutoff. Statistical significance for loci was Bonferroni corrected for 6 loci (P < 8.3 × 10(-3)). RLS symptoms were categorized into four groups: likely, possible, no symptoms, and unknown based on a mailed survey response. MEASUREMENTS AND RESULTS Prevalence of PLMI ≥ 15 was 33%. Subjects with PLMs were older, more likely to be male, and had more frequent RLS symptoms, a shorter total sleep time, and higher wake after sleep onset. Strong associations were found at all loci except one. Highest associations for PLMI > 15/h were obtained using a multivariate model including age, sex, sleep disturbances, and the best SNPs for each loci, yielding the following odds ratios (OR) and P values: BTBD9 rs3923809(A) OR = 1.65, P = 1.5×10(-8); TOX3/BC034767 rs3104788(T) OR = 1.35, P = 9.0 × 10(-5); MEIS1 rs12469063(G) OR = 1.38, P = 2.0 × 10(-4); MAP2K5/SKOR1 rs6494696(G) OR = 1.24, P = 1.3×10(-2); and PTPRD(A) rs1975197 OR = 1.31, P = 6.3×10(-3). Linear regression models also revealed significant PLM effects for BTBD9, TOX3/BC034767, and MEIS1. Co-varying for RLS symptoms only modestly reduced the genetic associations. CONCLUSIONS Single nucleotide polymorphisms demonstrated to increase risk of RLS are strongly linked to increased PLM as well, although some loci may have more effects on one versus the other phenotype.
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Affiliation(s)
- Hyatt Moore
- Center for Sleep Sciences and Medicine, Stanford University, Palo Alto, CA
- Department of Electrical Engineering, Stanford University, Palo Alto, CA
| | - Juliane Winkelmann
- Center for Sleep Sciences and Medicine, Stanford University, Palo Alto, CA
| | - Ling Lin
- Center for Sleep Sciences and Medicine, Stanford University, Palo Alto, CA
| | - Laurel Finn
- Department of Population Health Sciences, University of Wisconsin-Madison, Madison, WI
| | - Paul Peppard
- Department of Population Health Sciences, University of Wisconsin-Madison, Madison, WI
| | - Emmanuel Mignot
- Center for Sleep Sciences and Medicine, Stanford University, Palo Alto, CA
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186
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Genetische Aspekte der REM-Schlaf-Verhaltensstörung. SOMNOLOGIE 2014. [DOI: 10.1007/s11818-014-0679-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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187
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de Biase S, Merlino G, Lorenzut S, Valente M, Gigli GL. ADMET considerations when prescribing novel therapeutics to treat restless legs syndrome. Expert Opin Drug Metab Toxicol 2014; 10:1365-80. [DOI: 10.1517/17425255.2014.952629] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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188
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Schulte EC, Kousi M, Tan PL, Tilch E, Knauf F, Lichtner P, Trenkwalder C, Högl B, Frauscher B, Berger K, Fietze I, Hornyak M, Oertel WH, Bachmann CG, Zimprich A, Peters A, Gieger C, Meitinger T, Müller-Myhsok B, Katsanis N, Winkelmann J. Targeted resequencing and systematic in vivo functional testing identifies rare variants in MEIS1 as significant contributors to restless legs syndrome. Am J Hum Genet 2014; 95:85-95. [PMID: 24995868 DOI: 10.1016/j.ajhg.2014.06.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 06/10/2014] [Indexed: 11/19/2022] Open
Abstract
Restless legs syndrome (RLS) is a common neurologic condition characterized by nocturnal dysesthesias and an urge to move, affecting the legs. RLS is a complex trait, for which genome-wide association studies (GWASs) have identified common susceptibility alleles of modest (OR 1.2-1.7) risk at six genomic loci. Among these, variants in MEIS1 have emerged as the largest risk factors for RLS, suggesting that perturbations in this transcription factor might be causally related to RLS susceptibility. To establish this causality, direction of effect, and total genetic burden of MEIS1, we interrogated 188 case subjects and 182 control subjects for rare alleles not captured by previous GWASs, followed by genotyping of ∼3,000 case subjects and 3,000 control subjects, and concluded with systematic functionalization of all discovered variants using a previously established in vivo model of neurogenesis. We observed a significant excess of rare MEIS1 variants in individuals with RLS. Subsequent assessment of all nonsynonymous variants by in vivo complementation revealed an excess of loss-of-function alleles in individuals with RLS. Strikingly, these alleles compromised the function of the canonical MEIS1 splice isoform but were irrelevant to an isoform known to utilize an alternative 3' sequence. Our data link MEIS1 loss of function to the etiopathology of RLS, highlight how combined sequencing and systematic functional annotation of rare variation at GWAS loci can detect risk burden, and offer a plausible explanation for the specificity of phenotypic expressivity of loss-of-function alleles at a locus broadly necessary for neurogenesis and neurodevelopment.
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Affiliation(s)
- Eva C Schulte
- Neurologische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany; Institut für Humangenetik, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Maria Kousi
- Center for Human Disease Modeling, Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Perciliz L Tan
- Center for Human Disease Modeling, Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Erik Tilch
- Institut für Humangenetik, Helmholtz Zentrum München, 85764 Munich, Germany; Institut für Humangenetik, Technische Universität München, 81675 Munich, Germany
| | - Franziska Knauf
- Institut für Humangenetik, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Peter Lichtner
- Institut für Humangenetik, Helmholtz Zentrum München, 85764 Munich, Germany; Institut für Humangenetik, Technische Universität München, 81675 Munich, Germany
| | - Claudia Trenkwalder
- Paracelsus Elena Klinik, 34128 Kassel, Germany; Klinik für Neurochirurgie, Georg August Universität, 37075 Göttingen, Germany
| | - Birgit Högl
- Department of Neurology, Medizinische Universität Innsbruck, 6020 Innsbruck, Austria
| | - Birgit Frauscher
- Department of Neurology, Medizinische Universität Innsbruck, 6020 Innsbruck, Austria
| | - Klaus Berger
- Institut für Epidemiologie und Sozialmedizin, Westfälische Wilhelms Universität Münster, 48149 Münster, Germany
| | - Ingo Fietze
- Zentrum für Schlafmedizin, Charité Universitätsmedizin, 10117 Berlin, Germany
| | - Magdolna Hornyak
- Neurologische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany; Interdisziplinäres Schmerzzentrum, Albert-Ludwigs Universität Freiburg, 79106 Freiburg, Germany; Diakoniewerk München-Maxvorstadt, 80799 Munich, Germany
| | - Wolfgang H Oertel
- Klinik für Neurologie, Philipps Universität Marburg, 35039 Marburg, Germany
| | - Cornelius G Bachmann
- Abteilung für Neurologie, Paracelsus Klinikum Osnabrück, 49076 Osnabrück, Germany; Klinische Neurophysiologie, Georg August Universität, 37075 Göttingen, Germany
| | - Alexander Zimprich
- Department of Neurology, Medizinische Universität Wien, 1090 Vienna, Austria
| | - Annette Peters
- Institute of Epidemiology II, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Christian Gieger
- Institute of Genetic Epidemiology, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Thomas Meitinger
- Institut für Humangenetik, Helmholtz Zentrum München, 85764 Munich, Germany; Institut für Humangenetik, Technische Universität München, 81675 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Bertram Müller-Myhsok
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; Max-Planck Institut für Psychiatrie München, 80804 Munich, Germany; Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Juliane Winkelmann
- Neurologische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany; Institut für Humangenetik, Helmholtz Zentrum München, 85764 Munich, Germany; Institut für Humangenetik, Technische Universität München, 81675 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; Department of Neurology and Neurosciences, Center for Sleep Sciences and Medicine, Stanford University, Palo Alto, CA 94304, USA.
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189
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Puligheddu M, Figorilli M, Aricò D, Raggi A, Marrosu F, Ferri R. Time structure of leg movement activity during sleep in untreated Parkinson disease and effects of dopaminergic treatment. Sleep Med 2014; 15:816-24. [DOI: 10.1016/j.sleep.2014.03.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 03/06/2014] [Accepted: 03/10/2014] [Indexed: 11/15/2022]
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190
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Earley CJ, Connor J, Garcia-Borreguero D, Jenner P, Winkelman J, Zee PC, Allen R. Altered brain iron homeostasis and dopaminergic function in Restless Legs Syndrome (Willis-Ekbom Disease). Sleep Med 2014; 15:1288-301. [PMID: 25201131 DOI: 10.1016/j.sleep.2014.05.009] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/15/2014] [Accepted: 05/27/2014] [Indexed: 12/31/2022]
Abstract
Restless legs syndrome (RLS), also known as Willis-Ekbom Disease (WED), is a sensorimotor disorder for which the exact pathophysiology remains unclear. Brain iron insufficiency and altered dopaminergic function appear to play important roles in the etiology of the disorder. This concept is based partly on extensive research studies using cerebrospinal fluid (CSF), autopsy material, and brain imaging indicating reduced regional brain iron and on the clinical efficacy of dopamine receptor agonists for alleviating RLS symptoms. Finding causal relations, linking low brain iron to altered dopaminergic function in RLS, has required however the use of animal models. These models have provided insights into how alterations in brain iron homeostasis and dopaminergic system may be involved in RLS. The results of animal models of RLS and biochemical, postmortem, and imaging studies in patients with the disease suggest that disruptions in brain iron trafficking lead to disturbances in striatal dopamine neurotransmission for at least some patients with RLS. This review examines the data supporting an iron deficiency-dopamine metabolic theory of RLS by relating the results from animal model investigations of the influence of brain iron deficiency on dopaminergic systems to data from clinical studies in patients with RLS.
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Affiliation(s)
- Christopher J Earley
- Department of Neurology, The Johns Hopkins Bayview Medical Center, Baltimore, MD, USA.
| | - James Connor
- Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | | | - Peter Jenner
- Neurodegenerative Diseases Research Group, Institute of Pharmaceutical Science, School of Biomedical Sciences, King's College, London, UK
| | - John Winkelman
- Brigham and Women's Hospital Sleep Health Center, Brighton, MA, USA
| | - Phyllis C Zee
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Richard Allen
- Department of Neurology, The Johns Hopkins Bayview Medical Center, Baltimore, MD, USA
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191
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Schulte EC, Kaffe M, Schormair B, Winkelmann J. Iron in Restless Legs Syndrome. Mov Disord Clin Pract 2014; 1:161-172. [PMID: 30363981 DOI: 10.1002/mdc3.12047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/07/2014] [Accepted: 04/18/2014] [Indexed: 12/14/2022] Open
Abstract
A link between restless legs syndrome (RLS) and iron has been recognized for several decades. Yet, the precise role that iron or other components of iron metabolism play in bringing about RLS is still a matter of debate. During the last few years, many new pieces of evidence from genetics, pathology, imaging, and clinical studies have surfaced. However, the way this evidence fits into the larger picture of RLS as a disease is not always easily understood. To provide a better understanding of the complex interplay between iron metabolism and RLS and highlight areas that need further elucidation, we systematically and critically review the current literature on the role of iron in RLS pathophysiology and treatment with a special emphasis on genetics, neuropathology, cell and animal models, imaging studies, and therapy.
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Affiliation(s)
- Eva C Schulte
- Neurologische Klinik und Poliklinik Klinikum rechts der Isar Technische Universität München Munich Germany.,Institut für Humangenetik Helmholtz Zentrum München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany
| | - Maria Kaffe
- Neurologische Klinik und Poliklinik Klinikum rechts der Isar Technische Universität München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany
| | - Barbara Schormair
- Institut für Humangenetik Helmholtz Zentrum München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany
| | - Juliane Winkelmann
- Neurologische Klinik und Poliklinik Klinikum rechts der Isar Technische Universität München Munich Germany.,Institut für Humangenetik Helmholtz Zentrum München Munich Germany.,Institut für Humangenetik Klinikum rechts der Isar Technische Universität München Munich Germany.,Munich Cluster for Systems Neurology (SyNergy) Munich Germany
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192
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Abstract
PURPOSE OF REVIEW Much recent progress has been made in understanding restless legs syndrome (RLS), focusing mainly on genetic predisposition and dysregulation of iron metabolism and the dopaminergic system. We provide in this review an update of the most recent scientific advances on the pathophysiology of primary RLS. RECENT FINDINGS Genome-wide association studies identified six genetic variants including MEIS1 and BTBD9 with potential relationships with iron. Brain iron level is low in RLS and neuropathological studies have shown significant decreases in dopamine D2 receptors in the putamen that correlated with RLS severity, and increased tyrosine hydroxylase in the substantia nigra. An overly activated dopaminergic system was reported in both animal and cell models of iron insufficiency thus suggesting that in at least a subgroup of RLS patients altered iron metabolism plays a role in the disorder. Also, dysregulation of iron uptake and storage within brain microvessels was recently reported and might play a role in a subgroup of RLS patients. SUMMARY RLS is a genetically heterogeneous complex trait with high prevalence but large phenotype variability. Current theories of RLS pathophysiology emphasize brain iron deficiency with abnormal dopaminergic consequences, together with a strong underlying genetic background.
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193
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Schulte EC, Schramm K, Schurmann C, Lichtner P, Herder C, Roden M, Gieger C, Peters A, Trenkwalder C, Högl B, Frauscher B, Berger K, Fietze I, Gross N, Stiasny-Kolster K, Oertel W, Bachmann CG, Paulus W, Zimprich A, Völzke H, Schminke U, Nauck M, Illig T, Meitinger T, Müller-Myhsok B, Prokisch H, Winkelmann J. Blood cis-eQTL analysis fails to identify novel association signals among sub-threshold candidates from genome-wide association studies in restless legs syndrome. PLoS One 2014; 9:e98092. [PMID: 24875634 PMCID: PMC4038519 DOI: 10.1371/journal.pone.0098092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 04/28/2014] [Indexed: 11/19/2022] Open
Abstract
Restless legs syndrome (RLS) is a common neurologic disorder characterized by nightly dysesthesias affecting the legs primarily during periods of rest and relieved by movement. RLS is a complex genetic disease and susceptibility factors in six genomic regions have been identified by means of genome-wide association studies (GWAS). For some complex genetic traits, expression quantitative trait loci (eQTLs) are enriched among trait-associated single nucleotide polymorphisms (SNPs). With the aim of identifying new genetic susceptibility factors for RLS, we assessed the 332 best-associated SNPs from the genome-wide phase of the to date largest RLS GWAS for cis-eQTL effects in peripheral blood from individuals of European descent. In 740 individuals belonging to the KORA general population cohort, 52 cis-eQTLs with pnominal<10−3 were identified, while in 976 individuals belonging to the SHIP-TREND general population study 53 cis-eQTLs with pnominal<10−3 were present. 23 of these cis-eQTLs overlapped between the two cohorts. Subsequently, the twelve of the 23 cis-eQTL SNPs, which were not located at an already published RLS-associated locus, were tested for association in 2449 RLS cases and 1462 controls. The top SNP, located in the DET1 gene, was nominally significant (p<0.05) but did not withstand correction for multiple testing (p = 0.42). Although a similar approach has been used successfully with regard to other complex diseases, we were unable to identify new genetic susceptibility factor for RLS by adding this novel level of functional assessment to RLS GWAS data.
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Affiliation(s)
- Eva C. Schulte
- Neurologische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institut für Humangenetik, Helmholtz Zentrum München, Munich, Germany
| | - Katharina Schramm
- Institut für Humangenetik, Helmholtz Zentrum München, Munich, Germany
- Institut für Humangenetik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Claudia Schurmann
- Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
| | - Peter Lichtner
- Institut für Humangenetik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Christian Herder
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), partner Düsseldorf, Düsseldorf, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), partner Düsseldorf, Düsseldorf, Germany
- University Clinics of Endocrinology and Diabetology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Christian Gieger
- Institute for Genetic Epidemiology, Helmholtz Zentrum München, Munich, Germany
| | - Annette Peters
- Institute for Epidemiology II, Helmholtz Zentrum München, Munich, Germany
| | - Claudia Trenkwalder
- Paracelsus Elena Klinik, Kassel, Germany
- Department of Neurosurgery, University Medical Center, Georg August Universität Göttingen, Göttingen, Germany
| | - Birgit Högl
- Neurologische Klinik, Medizinische Universität Innsbruck, Innsbruck, Austria
| | - Birgit Frauscher
- Neurologische Klinik, Medizinische Universität Innsbruck, Innsbruck, Austria
| | - Klaus Berger
- Institut für Epidemiologie und Sozialmedizin, Westfälische Wilhelms Universität Münster, Münster, Germany
| | - Ingo Fietze
- Zentrum für Schlafmedizin, Charite Universitätsmedizin, Berlin, Germany
| | - Nadine Gross
- Neurologische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Karin Stiasny-Kolster
- Neurologische Klinik, Philips Universität Marburg, Marburg, Germany
- Somnomar Institut für Medizinische Forschung und Schlafmedizin, Marburg, Germany
| | - Wolfgang Oertel
- Neurologische Klinik, Philips Universität Marburg, Marburg, Germany
| | | | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center, Georg August Universität Göttingen, Göttingen, Germany
| | | | - Henry Völzke
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Ulf Schminke
- Institute of Neurology, University Medicine Greifswald, Greifswald, Germany
| | - Matthias Nauck
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Thomas Illig
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, Munich, Germany
- Hannover Unified Biobank, Hannover Medical School, Hannover, Germany
| | - Thomas Meitinger
- Institut für Humangenetik, Helmholtz Zentrum München, Munich, Germany
- Institut für Humangenetik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Bertram Müller-Myhsok
- Max-Planck Institute for Psychiatry, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Holger Prokisch
- Institut für Humangenetik, Helmholtz Zentrum München, Munich, Germany
- Institut für Humangenetik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Juliane Winkelmann
- Neurologische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institut für Humangenetik, Helmholtz Zentrum München, Munich, Germany
- Institut für Humangenetik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- * E-mail:
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194
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Sleep/wake problems in Parkinson’s disease: pathophysiology and clinicopathologic correlations. J Neural Transm (Vienna) 2014; 121 Suppl 1:S3-13. [DOI: 10.1007/s00702-014-1239-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 05/06/2014] [Indexed: 11/25/2022]
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195
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Anderson CP, Leibold EA. Mechanisms of iron metabolism in Caenorhabditis elegans. Front Pharmacol 2014; 5:113. [PMID: 24904417 PMCID: PMC4033076 DOI: 10.3389/fphar.2014.00113] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 04/28/2014] [Indexed: 12/31/2022] Open
Abstract
Iron is involved in many biological processes essential for sustaining life. In excess, iron is toxic due to its ability to catalyze the formation of free radicals that damage macromolecules. Organisms have developed specialized mechanisms to tightly regulate iron uptake, storage and efflux. Over the past decades, vertebrate model organisms have led to the identification of key genes and pathways that regulate systemic and cellular iron metabolism. This review provides an overview of iron metabolism in the roundworm Caenorhabditis elegans and highlights recent studies on the role of hypoxia and insulin signaling in the regulation of iron metabolism. Given that iron, hypoxia and insulin signaling pathways are evolutionarily conserved, C. elegans provides a genetic model organism that promises to provide new insights into mechanisms regulating mammalian iron metabolism.
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Affiliation(s)
- Cole P Anderson
- Department of Medicine, Division of Hematology and Hematologic Malignancies and Department of Oncological Sciences, University of Utah, Salt Lake City UT, USA
| | - Elizabeth A Leibold
- Department of Medicine, Division of Hematology and Hematologic Malignancies and Department of Oncological Sciences, University of Utah, Salt Lake City UT, USA
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196
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Restless legs syndrome/Willis-Ekbom disease diagnostic criteria: updated International Restless Legs Syndrome Study Group (IRLSSG) consensus criteria--history, rationale, description, and significance. Sleep Med 2014; 15:860-73. [PMID: 25023924 DOI: 10.1016/j.sleep.2014.03.025] [Citation(s) in RCA: 941] [Impact Index Per Article: 94.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/23/2014] [Accepted: 03/25/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND In 2003, following a workshop at the National Institutes of Health, the International Restless Legs Syndrome Study Group (IRLSSG) developed updated diagnostic criteria for restless legs syndrome/Willis-Ekbom disease (RLS/WED). These criteria were integral to major advances in research, notably in epidemiology, biology, and treatment of RLS/WED. However, extensive review of accumulating literature based on the 2003 NIH/IRLSSG criteria led to efforts to improve the diagnostic criteria further. METHODS The clinical standards workshop, sponsored by the WED Foundation and IRLSSG in 2008, started a four-year process for updating the diagnostic criteria. That process included a rigorous review of research advances and input from clinical experts across multiple disciplines. After broad consensus was attained, the criteria were formally approved by the IRLSSG executive committee and membership. RESULTS Major changes are: (i) addition of a fifth essential criterion, differential diagnosis, to improve specificity by requiring that RLS/WED symptoms not be confused with similar symptoms from other conditions; (ii) addition of a specifier to delineate clinically significant RLS/WED; (iii) addition of course specifiers to classify RLS/WED as chronic-persistent or intermittent; and (iv) merging of the pediatric with the adult diagnostic criteria. Also discussed are supportive features and clinical aspects that are important in the diagnostic evaluation. CONCLUSIONS The IRLSSG consensus criteria for RLS/WED represent an international, interdisciplinary, and collaborative effort intended to improve clinical practice and promote further research.
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197
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Jung JS, Lee HJ, Cho CH, Kang SG, Yoon HK, Park YM, Moon JH, Yang HJ, Song HM, Kim L. Association between restless legs syndrome and CLOCK and NPAS2 gene polymorphisms in schizophrenia. Chronobiol Int 2014; 31:838-44. [PMID: 24824748 DOI: 10.3109/07420528.2014.914034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Previous studies have suggested that there is a genetic basis to restless legs syndrome (RLS) development. Occurrence of antipsychotic-induced RLS could also be due to differences in genetic susceptibility. We investigated whether CLOCK and NPAS2 gene polymorphisms are associated with RLS in schizophrenic patients on antipsychotics because RLS symptoms usually manifest during the evening and night. We assessed symptoms of RLS in 190 Korean schizophrenic patients on antipsychotics and divided the subjects into two groups according to the International Restless Legs Syndrome Study Group diagnostic criteria: (i) subjects who met all the criteria and (ii) the remaining subjects who did not meet all the criteria. We found a significant difference in the number of subjects with different genotype and allele carrier frequencies for the CLOCK gene (rs2412646) between the two groups (p = 0.031 and 0.010, respectively). Distribution of CLOCK haplotypes (rs2412646-rs1801260) was significantly different between schizophrenic patients with and without RLS (p = 0.021). However, the distributions of allelic, genotypic, and haplotypic variants of NPAS2 (rs2305160 and rs6725296) were not significantly different between the two groups. Our results suggest that CLOCK polymorphisms are associated with increased susceptibility of schizophrenic patients to RLS. We hypothesize that RLS in schizophrenia patients treated with antipsychotics may be a very mild akathisia that manifests during the night and is under control of circadian oscillation.
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Affiliation(s)
- Jin-Sook Jung
- Department of Psychiatry, College of Medicine, Korea University , Seoul , South Korea
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198
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de Biase S, Merlino G, Lorenzut S, Valente M, Gigli GL. Investigational approaches to therapies for restless legs syndrome. Expert Opin Investig Drugs 2014; 23:847-56. [DOI: 10.1517/13543784.2014.907793] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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199
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Frauscher B, Gabelia D, Mitterling T, Biermayr M, Bregler D, Ehrmann L, Ulmer H, Högl B. Motor events during healthy sleep: a quantitative polysomnographic study. Sleep 2014; 37:763-73, 773A-773B. [PMID: 24744455 DOI: 10.5665/sleep.3586] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Many sleep disorders are characterized by increased motor activity during sleep. In contrast, studies on motor activity during physiological sleep are largely lacking. We quantitatively investigated a large range of motor phenomena during polysomnography in physiological sleep. DESIGN Prospective polysomnographic investigation. SETTING Academic referral sleep laboratory. PARTICIPANTS One hundred healthy sleepers age 19-77 y were strictly selected from a representative population sample by a two-step screening procedure. INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Polysomnography according to American Academy of Sleep Medicine (AASM) standards was performed, and quantitative normative values were established for periodic limb movements in sleep (PLMS), high frequency leg movements (HFLM), fragmentary myoclonus (FM), neck myoclonus (NM), and rapid eye movement (REM)-related electromyographic (EMG) activity. Thirty-six subjects had a PLMS index > 5/h, 18 had a PLMS index > 15/h (90th percentile: 24.8/h). Thirty-three subjects had HFLM (90th percentile: four sequences/night). All subjects had FM (90th percentile 143.7/h sleep). Nine subjects fulfilled AASM criteria for excessive FM. Thirty-five subjects had NM (90th percentile: 8.8/h REM sleep). For REM sleep, different EMG activity measures for the mentalis and flexor digitorum superficialis muscles were calculated: the 90th percentile for phasic mentalis EMG activity for 30-sec epochs according to AASM recommendation was 15.6%, and for tonic mentalis EMG activity 2.6%. Twenty-five subjects exceeded the recently proposed phasic mentalis cutoff of 11%. None of the subjects exceeded the tonic mentalis cutoff of 9.6%. CONCLUSION Quantification of motor phenomena is a basic prerequisite to develop normative values, and is a first step toward a more precise description of the various motor phenomena present during sleep. Because rates of motor events were unexpectedly high even in physiological sleep, the future use of normative values for both research and clinical routine is essential.
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Affiliation(s)
- Birgit Frauscher
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - David Gabelia
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Thomas Mitterling
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Marlene Biermayr
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Deborah Bregler
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Laura Ehrmann
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Hanno Ulmer
- Institute of Medical Statistics, Informatics and Health Economics, Innsbruck Medical University, Innsbruck, Austria
| | - Birgit Högl
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
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200
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Abstract
Restless legs syndrome/Willis Ekbom disease (RLS/WED) has been recognized as a significant medical disorder since the 17th century. It was studied mostly in the last 50 years in relation to increasing interest in sleep medicine and health-related quality of life. This led to recognition that the disease is not well characterized as restless feelings in the legs. These symptoms are reported in many situations, but the subjective experience of RLS/WED patients differs from that experienced by others. Thus a new name has been introduced that avoids problems of symptom definition of a disease by naming it after those who first characterized it, i.e. 'Willis Ekbom disease'. This article emphasizes the importance of RLS/WED for psychiatry. The disease carries significant increased risk for depression and anxiety disorders. Treatment requires consideration of these co-morbid disorders. RLS/WED can exacerbate or even engender psychiatric disease, so treatment of psychiatric disease should also include consideration of RLS/WED. The need for attention to RLS/WED is particularly significant for depression. Most anti-depressants exacerbate or can even engender RLS/WED. Thus this article seeks to introduce RLS/WED in relation to psychiatric practice. It presents the RLS/WED disease, its overlap with psychiatry and the current treatment options.
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Affiliation(s)
- Richard P Allen
- Department of Nerology, Johns Hopkins University , Baltimore, Maryland , USA
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