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DelRosso LM, Mogavero MP, Bruni O, Ferri R. Restless Legs Syndrome and Restless Sleep Disorder in Children. Sleep Med Clin 2023; 18:201-212. [PMID: 37120162 DOI: 10.1016/j.jsmc.2023.01.008] [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: 05/01/2023]
Abstract
Restless legs syndrome (RLS) affects 2% of children presenting with symptoms of insomnia, restless sleep, decreased quality of life, and effects on cognition and behavior. The International RLS Study Group and the American Academy of Sleep Medicine have published guidelines for the diagnosis and treatment of RLS in children. Restless sleep disorder has been recently identified in children and presents with frequent movements during sleep and daytime symptoms with polysomnography findings of at least 5 large muscle movements at night. Treatment options for both disorders include iron supplementation, either oral or intravenous with improvement in nighttime and daytime symptoms.
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Affiliation(s)
- Lourdes M DelRosso
- University of California San Francisco, Fresno, USA; University Sleep and Pulmonary Associates, 6733 North Willow Avenue, Unit 107, Fresno, CA 93710, USA.
| | - Maria Paola Mogavero
- Institute of Molecular Bioimaging and Physiology, National Research Council, Milan, Italy; Division of Neuroscience, Sleep Disorders Center, San Raffaele Scientific Institute, Milan, Italy; Centro di Medicina Del Sonno, IRCCS Ospedale San Raffaele, Turro, Via Stamira D'Ancona, 20, Milano 20127, Italy
| | - Oliviero Bruni
- Department of Social and Developmental Psychology, Sapienza University, Via dei Marsi 78, Rome 00185, Italy
| | - Raffaele Ferri
- Department of Neurology I.C., Sleep Research Centre, Oasi Research Institute - IRCCS, Via C Ruggero 73, Troina 94018, Italy
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2
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Woods S, Basco J, Clemens S. Effects of iron-deficient diet on sleep onset and spinal reflexes in a rodent model of Restless Legs Syndrome. Front Neurol 2023; 14:1160028. [PMID: 37273717 PMCID: PMC10234126 DOI: 10.3389/fneur.2023.1160028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023] Open
Abstract
Restless Legs Syndrome (RLS) is a common sensorimotor and a sleep disorder that affects 2.5-10% of the European and North American populations. RLS is also often associated with periodic leg movements during sleep (PLMS). Despite ample evidence of genetic contributions, the underlying mechanisms that elicit the sensory and motor symptoms remain unidentified. Clinically, RLS has been correlated with an altered central iron metabolism, particularly in the brain. While several animal models have been developed to determine the outcome of an altered iron homeostasis on brain function, the potential role of an altered iron homeostasis on sleep and sensorimotor circuits has not yet been investigated. Here, we utilize a mouse model to assess the effects of an iron-deficient (ID) but non-anemic state on sleep time and episodes, and sensorimotor reflexes in male and female mice. We found that animals on the ID diet displayed an increased expression of the transferrin receptor in the spinal cord, confirming the results of previous studies that focused only on the impact of ID in the brain. We also demonstrate that the ID diet reduced hematocrit levels compared to controls but not into the anemic range, and that animals on the ID diet exhibited RLS-like symptoms with regard to sleep onset and spinal cord reflex excitability. Interestingly, the effects on the spinal cord were stronger in females than in males, and the ID diet-induced behaviors were rescued by the return of the animals to the control diet. Taken together, these results demonstrate that diet-induced ID changes to CNS function are both inducible and reversible, and that they mimic the sleep and sensorimotor RLS symptoms experienced in the clinic. We therefore propose replacing the commonly used phrase "brain iron deficiency" (BID) hypothesis in the RLS research field with the term "iron deficiency in the central nervous system" (ID-CNS), to include possible effects of altered iron levels on spinal cord function.
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Hermann W, Flemming T, Brandt MD, Langner S, Reichmann H, Storch A. Asymmetry of Periodic Leg Movements in Sleep (PLMS) in Parkinson's Disease. JOURNAL OF PARKINSONS DISEASE 2021; 10:255-266. [PMID: 31609696 DOI: 10.3233/jpd-191667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Periodic limb movements in sleep (PLMS) are repetitive movements usually of the legs strongly associated with Restless-legs syndrome (RLS), which appear more frequently in males, older age and other sleep disturbances, such as sleep-disordered breathing (SDB). Patients with Parkinson's disease (PD) suffer from various sleep disturbances including REM sleep behavior disorder, RLS and PLMS. Although a dopaminergic pathophysiology of PLMS is discussed, no systematic data on PLMS side-to-side distribution in PD and its correlation with asymmetry of motor symptoms are available. OBJECTIVE This study aimed at elucidating PLMS asymmetry in correlation to that of motor symptoms in PD compared to SDB and RLS. METHODS Cross-sectional, retrospective analysis of two polysomnography (PSG) recordings per patient scoring PLMS separately for both legs. RESULTS Of 105 patients (44 PD, 44 age- and sex-matched SDB and 17 RLS patients) PLMS measures (number of PLM, PLM-Index, PLM-arousal index) showed significant side-to-side differences in all disease entities in both PSGs (P < 0.001; Wilcoxon rank test). PLM-Index asymmetry (PLM-I difference of >5/h between both sides) was observed less frequently in PD (34% of patients) compared to RLS (77% , P < 0.05) and SDB (59% , P < 0.05; χ2 test). In asymmetric PD patients, predominant side of PLMS was more stable than in SDB and RLS comparing the two PSGs, but we did not detect an agreement between PLMS predominant side with that of motor symptoms in PD patients. CONCLUSIONS Only the minority of PD patients shows asymmetric PLMS distribution with relatively high night-to-night stability but no correlation with motor symptom asymmetry.
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Affiliation(s)
- Wiebke Hermann
- Department of Neurology, Technische Universität Dresden, Dresden, Germany.,Interdisciplinary Sleep Centre, Departments of Neurology and Internal Medicine I, Technische Universität Dresden, Dresden, Germany.,Department of Neurology, University of Rostock, Rostock, Germany.,German Center for Neurodegenerative Diseases (DZNE) Rostock, Rostock, Germany
| | - Theresa Flemming
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Moritz D Brandt
- Department of Neurology, Technische Universität Dresden, Dresden, Germany.,Interdisciplinary Sleep Centre, Departments of Neurology and Internal Medicine I, Technische Universität Dresden, Dresden, Germany.,German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Simona Langner
- Interdisciplinary Sleep Centre, Departments of Neurology and Internal Medicine I, Technische Universität Dresden, Dresden, Germany
| | - Heinz Reichmann
- Department of Neurology, Technische Universität Dresden, Dresden, Germany
| | - Alexander Storch
- Department of Neurology, University of Rostock, Rostock, Germany.,German Center for Neurodegenerative Diseases (DZNE) Rostock, Rostock, Germany
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4
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Gossard TR, Trotti LM, Videnovic A, St Louis EK. Restless Legs Syndrome: Contemporary Diagnosis and Treatment. Neurotherapeutics 2021; 18:140-155. [PMID: 33880737 PMCID: PMC8116476 DOI: 10.1007/s13311-021-01019-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2021] [Indexed: 12/12/2022] Open
Abstract
Restless legs syndrome (RLS) is characterized by an uncomfortable urge to move the legs while at rest, relief upon movement or getting up to walk, and worsened symptom severity at night. RLS may be primary (idiopathic) or secondary to pregnancy or a variety of systemic disorders, especially iron deficiency, and chronic renal insufficiency. Genetic predisposition with a family history is common. The pathogenesis of RLS remains unclear but is likely to involve central nervous system dopaminergic dysfunction, as well as other, undefined contributing mechanisms. Evaluation begins with a thorough history and examination, and iron measures, including ferritin and transferrin saturation, should be checked at presentation and with worsened symptoms, especially when augmentation develops. Augmentation is characterized by more intense symptom severity, earlier symptom occurrence, and often, symptom spread from the legs to the arms or other body regions. Some people with RLS have adequate symptom control with non-pharmacological measures such as massage or temperate baths. First-line management options include iron-replacement therapy in those with evidence for reduced body-iron stores or, alternatively, with prescribed gabapentin or pregabalin, and dopamine agonists such as pramipexole, ropinirole, and rotigotine. Second-line therapies include intravenous iron infusion in those who are intolerant of oral iron and/or those having augmentation with intense, severe RLS symptoms, and opioids including tramadol, oxycodone, and methadone. RLS significantly impacts patients' quality of life and remains a therapeutic area sorely in need of innovation and a further pipeline of new, biologically informed therapies.
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Affiliation(s)
- Thomas R Gossard
- Mayo Center for Sleep Medicine, 200 First Street SW, Rochester, MN, 55905, USA
| | | | | | - Erik K St Louis
- Mayo Center for Sleep Medicine, 200 First Street SW, Rochester, MN, 55905, USA.
- Departments of Neurology and Clinical and Translational Research, Mayo Clinic Southwest Wisconsin, La Crosse, Wisconsin, USA.
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5
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Chen P, Ijomone OM, Lee KH, Aschner M. Caenorhabditis elegans and its applicability to studies on restless legs syndrome. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2019; 84:147-174. [PMID: 31229169 DOI: 10.1016/bs.apha.2018.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Restless legs syndrome (RLS) is a common neurological disorder in the United States. This disorder is characterized by an irresistible urge to move the legs, although the symptoms vary in a wide range. The pathobiology of RLS has been linked to iron (Fe) deficiency and dopaminergic (DAergic) dysfunction. Several genetic factors have been reported to increase the risk of RLS. Caenorhabditis elegans (C. elegans) is a well-established animal model with a fully sequenced genome, which is highly conserved with mammals. Given the detailed knowledge of its genomic architecture, ease of genetic manipulation and conserved biosynthetic and metabolic pathways, as well as its small size, ease of maintenance, speedy generation time and large brood size, C. elegans provides numerous advantages in studying RLS-associated gene-environment interactions. Here we will review current knowledge about RLS symptoms, pathology and treatments, and discuss the application of C. elegans in RLS study, including the worm homologous genes and methods that could be performed to advance the pathophysiology RLS.
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Affiliation(s)
- Pan Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Omamuyovwi Meashack Ijomone
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States; Department of Human Anatomy, Federal University of Technology, Akure, Nigeria
| | - Kun He Lee
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States.
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6
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Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Agúndez JA. Genetics of restless legs syndrome: An update. Sleep Med Rev 2018; 39:108-121. [DOI: 10.1016/j.smrv.2017.08.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 10/19/2022]
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7
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Mantovani S, Smith SS, Gordon R, O'Sullivan JD. An overview of sleep and circadian dysfunction in Parkinson's disease. J Sleep Res 2018; 27:e12673. [PMID: 29493044 DOI: 10.1111/jsr.12673] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/15/2018] [Accepted: 01/15/2018] [Indexed: 12/18/2022]
Abstract
Sleep and circadian alterations are amongst the very first symptoms experienced in Parkinson's disease, and sleep alterations are present in the majority of patients with overt clinical manifestation of Parkinson's disease. However, the magnitude of sleep and circadian dysfunction in Parkinson's disease, and its influence on the pathophysiology of Parkinson's disease remains often unclear and a matter of debate. In particular, the confounding influences of dopaminergic therapy on sleep and circadian dysfunction are a major challenge, and need to be more carefully addressed in clinical studies. The scope of this narrative review is to summarise the current knowledge around both sleep and circadian alterations in Parkinson's disease. We provide an overview on the frequency of excessive daytime sleepiness, insomnia, restless legs, obstructive apnea and nocturia in Parkinson's disease, as well as addressing sleep structure, rapid eye movement sleep behaviour disorder and circadian features in Parkinson's disease. Sleep and circadian disorders have been linked to pathological conditions that are often co-morbid in Parkinson's disease, including cognitive decline, memory impairment and neurodegeneration. Therefore, targeting sleep and circadian alterations could be one of the earliest and most promising opportunities to slow disease progression. We hope that this review will contribute to advance the discussion and inform new research efforts to progress our knowledge in this field.
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Affiliation(s)
- Susanna Mantovani
- Faculty of Medicine, The University of Queensland, UQ Centre for Clinical Research, Herston, QLD, Australia.,Wesley Medical Research, Auchenflower, QLD, Australia.,Department of Neurology, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
| | - Simon S Smith
- Institute for Social Science Research (ISSR), The University of Queensland, Indooroopilly, Australia
| | - Richard Gordon
- Faculty of Medicine, The University of Queensland, UQ Centre for Clinical Research, Herston, QLD, Australia.,Wesley Medical Research, Auchenflower, QLD, Australia
| | - John D O'Sullivan
- Faculty of Medicine, The University of Queensland, UQ Centre for Clinical Research, Herston, QLD, Australia.,Wesley Medical Research, Auchenflower, QLD, Australia.,Department of Neurology, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
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8
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Khan FH, Ahlberg CD, Chow CA, Shah DR, Koo BB. Iron, dopamine, genetics, and hormones in the pathophysiology of restless legs syndrome. J Neurol 2017; 264:1634-1641. [PMID: 28236139 DOI: 10.1007/s00415-017-8431-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/16/2017] [Accepted: 02/18/2017] [Indexed: 12/16/2022]
Abstract
Restless legs syndrome (RLS) is a common, chronic neurologic condition, which causes a persistent urge to move the legs in the evening that interferes with sleep. Human and animal studies have been used to study the pathophysiologic state of RLS and much has been learned about the iron and dopamine systems in relation to RLS. Human neuropathologic and imaging studies have consistently shown decreased iron in different brain regions including substantia nigra and thalamus. These same areas also demonstrate a state of relative dopamine excess. While it is not known how these changes in dopamine or iron produce the symptoms of RLS, genetic and hormone studies of RLS have identified other biologic systems or genes, such as the endogenous opioid and melanocortin systems and BTBD9 and MEIS1, that may explain some of the iron or dopamine changes in relation to RLS. This manuscript will review what is known about the pathophysiology of RLS, especially as it relates to changes in iron, dopamine, genetics, and hormonal systems.
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Affiliation(s)
- Farhan H Khan
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Caitlyn D Ahlberg
- Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Christopher A Chow
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Divya R Shah
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA
| | - Brian B Koo
- Lippard Laboratory of Clinical Investigation, Division of Movement Disorders, Department of Neurology, Yale University School of Medicine, Room 710, West Haven VAMC, 950 Campbell Avenue, West Haven, CT, 06516, USA.
- Connecticut Veterans Affairs Medical Center, 950 Campbell Avenue, West Haven, CT, 06516, USA.
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9
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Högl B, Stefani A. Restless legs syndrome and periodic leg movements in patients with movement disorders: Specific considerations. Mov Disord 2017; 32:669-681. [DOI: 10.1002/mds.26929] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 12/21/2016] [Indexed: 12/25/2022] Open
Affiliation(s)
- Birgit Högl
- Department of Neurology; Medical University of Innsbruck; Innsbruck Austria
| | - Ambra Stefani
- Department of Neurology; Medical University of Innsbruck; Innsbruck Austria
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10
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Abstract
Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is a common movement disorder characterised by an uncontrollable urge to move because of uncomfortable, sometimes painful sensations in the legs with a diurnal variation and a release with movement. The pathophysiology is only partially known and a genetic component together with dopaminergic and brain iron dysregulation plays an important role. Secondary causes for RLS need to be excluded. Treatment depends on the severity and frequency of RLS symptoms, comprises non-pharmacological (eg lifestyle changes) and pharmacological interventions (eg dopaminergic medication, alpha-2-delta calcium channel ligands, opioids) and relieves symptoms only. Augmentation is the main complication of long-term dopaminergic treatment of RLS. This article will provide a clinically useful overview of RLS with provision of diagnostic criteria, differential diagnoses, possible investigations and different treatment strategies with their associated complications.
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11
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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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12
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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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13
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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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15
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Roco A, Jiménez-Jiménez FJ, Alonso-Navarro H, Martínez C, Zurdo M, Turpín-Fenoll L, Millán J, Adeva-Bartolomé T, Cubo E, Navacerrada F, Rojo-Sebastián A, Rubio L, Calleja M, Plaza-Nieto JF, Pilo-de-la-Fuente B, Arroyo-Solera M, García-Martín E, Agúndez JAG. MAPT1 gene rs1052553 variant is unrelated with the risk for restless legs syndrome. J Neural Transm (Vienna) 2012; 120:463-7. [DOI: 10.1007/s00702-012-0897-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 09/03/2012] [Indexed: 10/27/2022]
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Clinical and polysomnographic features of a large Turkish pedigree with restless leg syndrome and periodic limb movements. Sleep Breath 2012; 17:741-6. [PMID: 22855331 DOI: 10.1007/s11325-012-0756-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 06/08/2012] [Accepted: 07/17/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE Restless leg syndrome (RLS) and periodic limb movements (PLMS) are common neurological diseases often associated with insomnia. A familial aggregation in RLS has been identified since it was first described; however, inheritance patterns of RLS/PLMS are poorly understood and their exact pathophysiology is not well-known. We have identified a Turkish pedigree with RLS/PLMS, which is a rare condition, in five generations of a family, including nine affected family members. METHODS A detailed clinical evaluation of the family was conducted with the help of polysomnographic recording, electrophysiological findings, and biochemical parameters. RESULTS The proband is a 38-year-old male member of the family who first started to show symptoms at the age of 29. All the patients from this family have been diagnosed with RLS, according to the criteria of the International RLS Study Group. Disease onset was early in all cases and even earlier in the younger generation. Three affected individuals also had PLMS on polysomnographic recordings. CONCLUSION To our knowledge, this is the first Turkish family in which nine individuals in five generations are affected. We suggest an important effect of anticipation and genetic impact of the diseases and describe specific clinical features. Further investigation of clinical, genetic, and biochemical similarities between PLMS and RLS may yield important clues, adding to our understanding of the pathophysiology of these common diseases.
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DeAndrade MP, Johnson RL, Unger EL, Zhang L, van Groen T, Gamble KL, Li Y. Motor restlessness, sleep disturbances, thermal sensory alterations and elevated serum iron levels in Btbd9 mutant mice. Hum Mol Genet 2012; 21:3984-92. [PMID: 22678064 DOI: 10.1093/hmg/dds221] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Restless legs syndrome (RLS), also known as Willis-Ekbom disease, is a sensory-motor neurological disorder with a circadian component. RLS is characterized by uncomfortable sensations in the extremities, generally at night or during sleep, which often leads to an uncontrollable urge to move them for relief. Recently, genomic studies identified single-nucleotide polymorphisms in BTBD9, along with three other genes, as being associated with a higher risk of RLS. Little is known about the function of BTBD9 or its potential role in the pathophysiology of RLS. We therefore examined a line of Btbd9 mutant mice we recently generated for phenotypes similar to symptoms found in RLS patients. We observed that the Btbd9 mutant mice had motor restlessness, sensory alterations likely limited to the rest phase, and decreased sleep and increased wake times during the rest phase. Additionally, the Btbd9 mutant mice had altered serum iron levels and monoamine neurotransmitter systems. Furthermore, the sensory alterations in the Btbd9 mutant mice were relieved using ropinirole, a dopaminergic agonist widely used for RLS treatment. These results, taken together, suggest that the Btbd9 mutant mice model several characteristics similar to RLS and would therefore be the first genotypic mouse model of RLS. Furthermore, our data provide further evidence that BTBD9 is involved in RLS, and future studies of the Btbd9 mutant mice will help shine light on its role in the pathophysiology of RLS. Finally, our data argue for the utility of Btbd9 mutant mice to discover and screen novel therapeutics for RLS.
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Affiliation(s)
- Mark P DeAndrade
- Interdisciplinary Program in Biomedical Sciences and Department of Neurology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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18
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Durmer JS, Quraishi GH. Restless legs syndrome, periodic leg movements, and periodic limb movement disorder in children. Pediatr Clin North Am 2011; 58:591-620. [PMID: 21600344 DOI: 10.1016/j.pcl.2011.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The characteristic symptoms of restless legs syndrome (RLS) have been known for hundreds of years and were first reported in medicine in the 1600s. Clinicians must consider potential mimics, comorbid, and associated conditions when evaluating children with RLS symptoms. The traditional differentiation of RLS from periodic limb movement disorder (PLMD) is noted in children as well as adults. Because current pediatric RLS research is sparse, this article provides the most up-to-date evidence-based as well as consensus opinion-based information on the subject of childhood RLS and PLMD. Prevalence, pathophysiology, diagnosis, treatment, and clinical associations are discussed.
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Schormair B, Winkelmann J. Genetics of Restless Legs Syndrome: Mendelian, Complex, and Everything in Between. Sleep Med Clin 2011. [DOI: 10.1016/j.jsmc.2011.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Abstract
Restless legs syndrome (RLS) is a sleep and movement disorder that affects up to 15% of the population across the lifespan. Many health care providers have doubted its validity as an illness and are uncertain as to the implications of health care outcomes. The cause of RLS is unknown. Common treatment options include dopaminergics, benzodiazepines, and opioids; however, the pharmacogenetic mechanisms of treatment are unknown. One of the greatest genetic discoveries in 2007 was the identification of genetic variance associated with RLS. There is, however, a lack of knowledge related to RLS and its genetic basis. Therefore, the purposes of this article are to (a) provide information about the science of clinical care related to RLS; (b) present a systematic review of the literature on the status of genetics/genomics of RLS, including the discovery of associated genetic variance; and (c) identify implications of the current state of the science for health care providers and biobehavioral researchers. With the continuing genetic discoveries in RLS, health care providers, specifically nurses who play a major role in research, genetic counseling, and education, need to understand the implications of this sleep and movement disorder for patients across the lifespan.
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Affiliation(s)
- Norma G Cuellar
- Capstone College of Nursing, The University of Alabama, Box 870358,Tuscaloosa, AL 35487, USA.
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21
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Erichsen D, Ferri R, Gozal D. Ropinirole in restless legs syndrome and periodic limb movement disorder. Ther Clin Risk Manag 2010; 6:173-82. [PMID: 20421915 PMCID: PMC2857615 DOI: 10.2147/tcrm.s6717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Indexed: 11/23/2022] Open
Abstract
Restless legs syndrome and periodic limb movement disorder of sleep are now recognized as prevalent, distinct, yet overlapping disorders affecting all age groups. Although delineation of the mechanisms underlying these disorders continues to be the focus of very intense research efforts, it has become apparent that there is a prominent role for dopaminergic agents in the clinical management of these patients. Among the various dopaminergic drugs, ropinirole has undergone relatively intense and critical scrutiny, and appears to provide a safe and efficacious treatment option for patients with these two conditions. The more recent development of a controlled formulation for this drug is likely to yield additional benefits such as improved adherence and reduced fluctuations in daytime and nighttime symptoms. However, there is not enough evidence at this time to support such assumption.
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Affiliation(s)
- Daniel Erichsen
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
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Abstract
Restless legs syndrome (RLS) is a common neurological sensory-motor disorder that is characterized by intense restlessness and unpleasant creeping sensations deep inside the lower legs. Symptoms appear when the legs are at rest and are worst in the evening and at night. They force patients to keep moving their legs, and often to get out of bed and wander about. Periodic limb movements (PLMS) are also common during sleep amongst those suffering from RLS, and sleep efficiency is severely reduced. There are idiopathic as well as symptomatic forms of RLS, the latter being associated with e.g. pregnancy, iron deficiency and chronic renal failure. A family history of RLS is very common and pedigrees in these cases suggest an autosomal-dominant transmission with high penetrance. Genetic investigations have been performed in order to identify genes associated with RLS. Several loci have been found (on chromosomes 12q, 14q, 9p, 2q, 20p and 16p). Pathophysiology of RLS remains incompletely understood. However, advanced brain imaging studies and positive results of dopaminergic treatment suggest that RLS may be generated by dopamine dysfunction locally within the central nervous system. At present, there is a wide range of treatment options including levodopa, dopamine agonists, opioids, benzodiazepines, antiepileptic drugs and iron supplements.
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Affiliation(s)
- Karl Ekbom
- Department of Neurology, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sleep Disorders Center, Avesta Hospital, Stockholm, Sweden.
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Abstract
Restless legs syndrome (RLS) is a highly familial trait with heritability estimates of about 50%. It is a polygenetic disorder in which a number of variants contribute to the phenotype. Linkage studies in families with RLS revealed several loci but have not yet led to the identification of disease-causing sequence variants. Phenocopies, nonpenetrance, and possible intrafamilial heterogeneity make it difficult to define the exact candidate region. Genome-wide association studies identified variants within intronic or intergenic regions of MEIS1, BTBD9, and MAP2K5/LBOXCOR1. Carriers of one risk allele had a 50% increased risk of developing RLS. MEIS1 and LBXCOR1 are developmental factors and raise new pathophysiologic questions for RLS. These variants have weak and moderate effects and increase the risk of developing RLS. It is still possible that strong effects explain the occurrence of RLS in families. Therefore, linkage and association studies should be used congruently to dissect the complete genetic architecture of RLS.
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Affiliation(s)
- Juliane Winkelmann
- Helmholz Center Munich, National Research Center for Environment and Health, Munich Institute of Human Genetics, Ingolstaedter Landstrasse 1, D-85764 Munich-Neuherberg, Germany.
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Cuellar NG, Ratcliffe SJ. Restless legs syndrome in type 2 diabetes: implications to diabetes educators. DIABETES EDUCATOR 2008; 34:218-34. [PMID: 18375774 DOI: 10.1177/0145721708314180] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The purpose of this study was to provide a background of restless legs syndrome (RLS), present the prevalence and demographic findings of a descriptive study of type 2 diabetes with RLS, and provide implications to diabetes educators on the management and education of RLS. METHODS Participants with type 2 diabetes who met the diagnostic criteria for RLS based on the International RLS Study Group Criteria were recruited from the PENN Rodebaugh Diabetes Center from July 2005 through September 2006. Participants who met inclusion and exclusion criteria were mailed a survey to collect data. RESULTS Of 121 patients with type 2 diabetes, 54 (45%) of the screened sample met the 4 diagnostic criteria for RLS. Of those who met the inclusion and exclusion criteria of the primary study, 18 patients with type 2 diabetes with RLS participated in this study. Along with diabetes, the participants had a variety of comorbid health conditions including hypertension, neuropathies, rheumatoid arthritis, renal failure, and irritable bowel syndrome. Only one third of the participants were being treated for RLS. Thirty-nine percent of the participants with type 2 diabetes were using insulin to manage their diabetes with other oral agents. CONCLUSIONS RLS is a sleep disorder that may affect the management of type 2 diabetes. Diabetes educators must know that sleep disorders can affect long-term health outcomes, and RLS is frequently seen in this cohort of patients.
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Affiliation(s)
- Norma G Cuellar
- The School of Nursing, at the University of Pennsylvania (Dr Cuellar)
| | - Sarah J Ratcliffe
- The Center for Clinical Epidemiology and Biostatistics School of Medicine, at the University of Pennsylvania (Dr Ratcliffe)
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25
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Karroum E, Konofal E, Arnulf I. [Restless-legs syndrome]. Rev Neurol (Paris) 2008; 164:701-21. [PMID: 18656214 DOI: 10.1016/j.neurol.2008.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 04/10/2008] [Accepted: 06/06/2008] [Indexed: 11/26/2022]
Abstract
Restless-legs syndrome (RLS) is a sensorimotor disorder, characterized by an irresistible urge to move the legs usually accompanied or caused by uncomfortable and unpleasant sensations. It begins or worsens during periods of rest or inactivity, is partially or totally relieved by movements and is exacerbated or occurs at night and in the evening. RLS sufferers represent 2 to 3% of the general population in Western countries. Supportive criteria include a family history, the presence of periodic-leg movements (PLM) when awake or asleep and a positive response to dopaminergic treatment. The RLS phenotypes include an early onset form, usually idiopathic with a familial history and a late onset form, usually secondary to peripheral neuropathy. Recently, an atypical RLS phenotype without PLM and l-DOPA resistant has been characterized. RLS can occur in childhood and should be distinguished from attention deficit/hyperactivity disorder, growing pains and sleep complaints in childhood. RLS should be included in the diagnosis of all patients consulting for sleep complaints or discomfort in the lower limbs. It should be differentiated from akathisia, that is, an urge to move the whole body without uncomfortable sensations. Polysomnographic studies and the suggested immobilization test can detect PLM. Furthermore, an l-DOPA challenge has recently been validated to support the diagnosis of RLS. RLS may cause severe-sleep disturbances, poor quality of life, depressive and anxious symptoms and may be a risk factor for cardiovascular disease. In most cases, RLS is idiopathic. It may also be secondary to iron deficiency, end-stage renal disease, pregnancy, peripheral neuropathy and drugs, such as antipsychotics and antidepressants. The small-fiber neuropathy can mimic RLS or even trigger it. RLS is associated with many neurological and sleep disorders including Parkinson's disease, but does not predispose to these diseases. The pathophysiology of RLS includes an altered brain-iron metabolism, a dopaminergic dysfunction, a probable role of pain control systems and a genetic susceptibility with nine loci and three polymorphisms in genes serving developmental functions. RLS treatment begins with the elimination of triggering factors and iron supplementation when deficient. Mild or intermittent RLS is usually treated with low doses of l-DOPA or codeine; the first-line treatment for moderate to severe RLS is dopaminergic agonists (pramipexole, ropinirole, rotigotine). In severe, refractory or neuropathy-associated RLS, antiepileptic (gabapentin, pregabalin) or opioid (oxycodone, tramadol) drugs can be used.
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Affiliation(s)
- E Karroum
- UF pathologies du sommeil, groupe hospitalier Pitié-Salpêtrière, Assistance publique-Hôpitaux de Paris, pavillon Marguerite-Bottard, Paris cedex, France.
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Winkelmann J, Polo O, Provini F, Nevsimalova S, Kemlink D, Sonka K, Högl B, Poewe W, Stiasny-Kolster K, Oertel W, de Weerd A, Strambi LF, Zucconi M, Pramstaller PP, Arnulf I, Trenkwalder C, Klein C, Hadjigeorgiou GM, Happe S, Rye D, Montagna P. Genetics of restless legs syndrome (RLS): State-of-the-art and future directions. Mov Disord 2008; 22 Suppl 18:S449-58. [PMID: 17557342 DOI: 10.1002/mds.21587] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Several studies demonstrated that 60% of restless legs syndrome (RLS) patients have a positive family history and it has been suggested that RLS is a highly hereditary trait. To date, several loci have been mapped but no gene has been identified yet. Phenocopies and possible nonpenetrants made it difficult to detect a common segregating haplotype within the families. Defining the exact candidate region is hampered by possible intrafamilial, allelic, and nonallelic heterogeneity. One important prerequisite for future successful genetic studies in RLS is the availability of large and thoroughly phenotyped patients and family samples for linkage as well as association studies.
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Affiliation(s)
- Juliane Winkelmann
- Institute of Human Genetics, GSF-National Research Center for Environment and Health, Munich, Germany.
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27
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Martínez García M. Una revisión del síndrome de piernas inquietas. Semergen 2008. [DOI: 10.1016/s1138-3593(08)71854-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Pichler I, Hicks AA, Pramstaller PP. Restless legs syndrome: an update on genetics and future perspectives. Clin Genet 2007; 73:297-305. [DOI: 10.1111/j.1399-0004.2007.00937.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Tan EK. Genetics of restless legs syndrome: evidence for a hereditary disorder. J Neurol 2007. [DOI: 10.1007/s00415-007-5011-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Stefansson H, Rye DB, Hicks A, Petursson H, Ingason A, Thorgeirsson TE, Palsson S, Sigmundsson T, Sigurdsson AP, Eiriksdottir I, Soebech E, Bliwise D, Beck JM, Rosen A, Waddy S, Trotti LM, Iranzo A, Thambisetty M, Hardarson GA, Kristjansson K, Gudmundsson LJ, Thorsteinsdottir U, Kong A, Gulcher JR, Gudbjartsson D, Stefansson K. A genetic risk factor for periodic limb movements in sleep. N Engl J Med 2007; 357:639-47. [PMID: 17634447 DOI: 10.1056/nejmoa072743] [Citation(s) in RCA: 490] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND The restless legs syndrome (RLS) is a common neurologic disorder characterized by an irresistible urge to move the legs. It is a major cause of sleep disruption. Periodic limb movements in sleep are detectable in most patients with RLS and represent an objective physiological metric. METHODS To search for sequence variants contributing to RLS, we performed a genomewide association study and two replication studies. To minimize phenotypic heterogeneity, we focused on patients with RLS who had objectively documented periodic limb movements in sleep. We measured serum ferritin levels, since iron depletion has been associated with the pathogenesis of RLS. RESULTS In an Icelandic discovery sample of patients with RLS and periodic limb movements in sleep, we observed a genomewide significant association with a common variant in an intron of BTBD9 on chromosome 6p21.2 (odds ratio, 1.8; P=2x10(-9)). This association was replicated in a second Icelandic sample (odds ratio, 1.8; P=4x10(-4)) and a U.S. sample (odds ratio, 1.5; P=4x10(-3)). With this variant, the population attributable risk of RLS with periodic limb movements was approximately 50%. An association between the variant and periodic limb movements in sleep without RLS (and the absence of such an association for RLS without periodic limb movements) suggests that we have identified a genetic determinant of periodic limb movements in sleep (odds ratio, 1.9; P=1x10(-17)). Serum ferritin levels were decreased by 13% per allele of the at-risk variant (95% confidence interval, 5 to 20; P=0.002). CONCLUSIONS We have discovered a variant associated with susceptibility to periodic limb movements in sleep. The inverse correlation of the variant with iron stores is consistent with the suspected involvement of iron depletion in the pathogenesis of the disease.
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Vogl FD, Pichler I, Adel S, Pinggera GK, Bracco S, De Grandi A, Volpato CB, Aridon P, Mayer T, Meitinger T, Klein C, Casari G, Pramstaller PP. Restless legs syndrome: epidemiological and clinicogenetic study in a South Tyrolean population isolate. Mov Disord 2007; 21:1189-95. [PMID: 16685686 DOI: 10.1002/mds.20922] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Genetic contributions to restless legs syndrome (RLS) have been consistently recognized from population and family studies. To determine the clinical and genetic features of RLS in a population isolate and explore linkage to three previously described susceptibility loci on chromosomes 12q, 14q, and 9p, respectively, an isolated population in the South Tyrolean Alps was identified and 530 adults participated in the study. Using a two-step strategy, 47 patients with idiopathic RLS were ascertained. The prevalence in the population was 8.9%. Twenty-eight patients (59.6%) had at least one affected first-degree relative and were classified as hereditary cases. In a single extended pedigree, linkage to known RLS loci was investigated specifying autosomal dominant and recessive models; parametric and nonparametric multipoint linkage scores were computed. None of the calculated linkage scores was suggestive of linkage between RLS and any of the three investigated loci. This study was conducted in a population isolate providing for a homogeneous genetic and environmental background. The absence of a suggestive linkage signal at the three known RLS susceptibility loci is indicative of further locus heterogeneity of this frequent disorder and encourages further studies to unveil the genetic causes of RLS.
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Affiliation(s)
- Florian D Vogl
- Institute of Genetic Medicine, European Academy, Bolzano, Italy
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33
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Abstract
Restless legs syndrome (RLS), also known as Ekbom syndrome, is a common movement disorder with sensorimotor symptoms occurring during sleep and quiet wakefulness. The underlying cause for RLS is unknown but genetic influences play a strong part in the pathogenesis of RLS, particularly when the condition starts at a young age. This review explores the genetic basis of RLS and related phenotypic variations. Recently, three loci showing vulnerability to RLS have been described in French-Canadian and Italian families in chromosomes 12q, 14q and 9q, emphasising on an autosomal dominant mode of inheritance. These have been labelled RLS1, RLS2 and RLS3, respectively. However, specific causative mutations remain elusive and no linkage analysis has been identified so far in the candidate genes investigated in RLS.
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Affiliation(s)
- V Dhawan
- Regional Movement Disorders Unit, King's College Hospital, London, UK
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34
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Abstract
Sleep problems are extremely common during childhood, from infancy to adolescence. Despite the prevalence of sleep problems, childhood sleep disorders are often underrecognized and undiagnosed, despite being either preventable or treatable. Sleep impacts almost all aspects of a child's functioning, and thus the increased recognition and treatment of sleep disorders will positively affect a child's well-being. Children experience the same broad range of sleep disturbances encountered in adults, including sleep apnea, insomnia, parasomnia, delayed sleep phase, narcolepsy, and restless legs, but their clinical presentation, evaluation, and management may differ. Although snoring and sleep apnea may be the most common indication for an overnight sleep study in a child, one quarter of children presenting to a sleep clinic for evaluation will have a second sleep diagnosis, which is often nonrespiratory in nature. Especially in children, ruling out sleep apnea is rarely the end point of the sleep evaluation. Clinicians involved in sleep medicine must be prepared to recognize, evaluate, and manage plans for sleep disorders across the lifespan of the patient. This article will provide an updated review of nonrespiratory pediatric sleep disorders within a developmental framework.
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Affiliation(s)
- Melisa Moore
- Case Western Reserve University, Department of Psychology, Mather Memorial Building, No. 109, 10900 Euclid Ave, Cleveland, OH 44106, USA.
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35
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Pichler I, Marroni F, Volpato CB, Gusella JF, Klein C, Casari G, De Grandi A, Pramstaller PP. Linkage analysis identifies a novel locus for restless legs syndrome on chromosome 2q in a South Tyrolean population isolate. Am J Hum Genet 2006; 79:716-23. [PMID: 16960808 PMCID: PMC1592574 DOI: 10.1086/507875] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Accepted: 07/17/2006] [Indexed: 11/03/2022] Open
Abstract
Restless legs syndrome (RLS) is a common neurological condition with three loci (12q, 14q, and 9p) described so far, although none of these genes has yet been identified. We report a genomewide linkage scan of patients with RLS (n=37) assessed in a population isolate (n=530) of South Tyrol (Italy). Using both nonparametric and parametric analyses, we initially obtained suggestive evidence of a novel locus on chromosome 2q, with nominal evidence of linkage on chromosomes 5p and 17p. Follow-up genotyping yielded significant evidence of linkage (nonparametric LOD score 5.5, P
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Affiliation(s)
- Irene Pichler
- Institute of Genetic Medicine, European Academy, Bolzano, Italy
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36
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37
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Abstract
Restless legs syndrome (RLS) is a sensorimotor disorder characterized by an irresistible urge to move the limbs accompanied by uncomfortable sensations, leading to sleep disturbances. It is associated with psychiatric comorbidities and a decreased quality of life. RLS is common and most severe among females and the elderly. It may be primary or secondary to other conditions and may be familial. Linkage to several chromosomal loci have been demonstrated. The pathogenesis of RLS involves dopaminergic dysfunction, iron metabolism, and abnormalities in supraspinal inhibition. The mainstay of RLS therapy are dopamine agonists or levodopa. This article reviews the clinical characteristics, epidemiology, diagnosis, pathogenesis, and treatment of RLS.
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38
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Abstract
Several studies on restless legs syndrome (RLS) have suggested a substantial genetic contribution in the etiology of this sleep disorder. Clinical surveys of idiopathic RLS patients have shown that 40-90% report a positive family history. The clinical features have been compared between familial and sporadic cases and the only difference found was a younger age-at-onset in familial RLS. Despite several reports suggesting a genetic contribution to the etiology of idiopathic RLS, few molecular genetic studies have been carried out attempting to identify genes that can predispose to this disorder. In particular, genes encoding for the GABA A receptor subunits, the gene for the alpha1 subunit of the glycine receptor, and genes involved in dopaminergic transmission and metabolism have been analyzed, however no significant findings have been reported. Genomewide linkage analysis studies using microsatellite markers have identified three loci for RLS: on chromosome 12q, on chromosome 14q and on chromosome 9p. It is important to investigate whether further RLS families show linkage to one of these loci to discuss the contribution of these loci and to provide a prerequisite of a mutational screening and identification of the RLS genes.
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Affiliation(s)
- Juliane Winkelmann
- Institute of Human Genetics, GSF-National Research Center for Environment and Health, Ingolstädter Landstrasse 1, D-85764 Munich-Neuherberg, Germany.
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39
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Abstract
Restless legs syndrome (RLS) is a common, but often underdiagnosed, neurological disorder, which is characterised by an imperative urge to move the extremities associated with paraesthesias, worsening of symptoms at rest and in the evening or at night, and, as a consequence, sleep disturbances. RLS affects 1-10% of the population. The aetiology of RLS is unknown, but besides genetic factors the dopaminergic and opioidergic system may play a crucial role and new developments also point to an exciting iron-dopamine connection in the pathophysiology of this burdening disorder. Due to the limited disease-specific knowledge, current treatment strategies are not curative, but nevertheless may produce an effective and lasting relief of symptoms. Although clinically based treatment has focused on levodopa, opioids and benzodiazepines for a long time, evidence-based and clinical guidelines identify dopamine agonists as a first-line treatment for daily restless legs symptoms. These substances are now in the process of registration for this indication. Ropinirole is the first dopamine agonist that has been approved by the FDA in May 2005. In addition, several promising new therapies with nondopamine profiles are under development for RLS.
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Affiliation(s)
- Stephany Fulda
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, D-80804 Munich, Germany
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40
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Mata IF, Bodkin CL, Adler CH, Lin SC, Uitti RJ, Farrer MJ, Wszolek ZK. Genetics of restless legs syndrome. Parkinsonism Relat Disord 2006; 12:1-7. [PMID: 16399043 DOI: 10.1016/j.parkreldis.2005.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 08/23/2005] [Accepted: 08/26/2005] [Indexed: 11/30/2022]
Abstract
Restless legs syndrome (RLS) is a common disorder, although under-diagnosed, with a prevalence of up to 15% depending on the population sampled. Familial aggregation has been widely shown since Ekbom formerly described the condition in 1960; twin studies support a genetic contribution in the development of this disorder. Molecular genetic approaches have identified three genomic regions in RLS susceptibility, however no specific mutations have yet been identified. Herein, we review the current status of genetics in RLS, providing some methodological guidelines to help future research.
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Affiliation(s)
- Ignacio F Mata
- Department of Neuroscience, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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41
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Barrière G, Cazalets JR, Bioulac B, Tison F, Ghorayeb I. The restless legs syndrome. Prog Neurobiol 2005; 77:139-65. [PMID: 16300874 DOI: 10.1016/j.pneurobio.2005.10.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Revised: 10/19/2005] [Accepted: 10/21/2005] [Indexed: 10/25/2022]
Abstract
The restless legs syndrome (RLS) is one of the commonest neurological sensorimotor disorders at least in the Western countries and is often associated with periodic limb movements (PLM) during sleep leading to severe insomnia. However, it remains largely underdiagnosed and its underlying pathogenesis is presently unknown. Women are more affected than men and early-onset disease is associated with familial cases. A genetic origin has been suggested but the mode of inheritance is unknown. Secondary causes of RLS may share a common underlying pathophysiology implicating iron deficiency or misuse. The excellent response to dopaminegic drugs points to a central role of dopamine in the pathophysiology of RLS. Iron may also represent a primary factor in the development of RLS, as suggested by recent pathological and brain imaging studies. However, the way dopamine and iron, and probably other compounds, interact to generate the circadian pattern in the occurrence of RLS and PLM symptoms remains unknown. The same is also the case for the level of interaction of the two compounds within the central nervous system (CNS). Recent electrophysiological and animals studies suggest that complex spinal mechanisms are involved in the generation of RLS and PLM symptomatology. Dopamine modulation of spinal reflexes through dopamine D3 receptors was recently highlighted in animal models. The present review suggests that RLS is a complex disorder that may result from a complex dysfunction of interacting neuronal networks at one or several levels of the CNS and involving numerous neurotransmitter systems.
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Affiliation(s)
- G Barrière
- Laboratoire de Neurophysiologie, UMR-CNRS 5543, Université Bordeaux 2, Bordeaux, France
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42
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Reutens S, Sachdev PS. Periodic limb movements and other movement disorders in sleep: neuropsychiatric dimensions. Int Rev Psychiatry 2005; 17:283-92. [PMID: 16194801 DOI: 10.1080/09540260500104557] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Movement disorders such as Parkinson's disease and Tourette's syndrome, primarily manifest during wakefulness, intrude into sleep. There are some disorders, however, such as periodic limb movements in sleep, restless legs syndrome, paroxysmal nocturnal dystonia, bruxism, and somnambulism, which occur primarily during sleep. The diagnosis and management of these disorders pose a challenge to neuropsychiatric practice, not only because they may be difficult to distinguish from other neuropsychiatric disorders, but also because psychiatric disorders are often co-morbid with them. Study of these disorders is necessary for an understanding of the interaction of sleep and movement, and how disturbance in one may affect the other.
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Wetter TC, Winkelmann J, Eisensehr I. Current treatment options for restless legs syndrome. Expert Opin Pharmacother 2005; 4:1727-38. [PMID: 14521483 DOI: 10.1517/14656566.4.10.1727] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Restless legs syndrome (RLS) is a common but often underdiagnosed neurological disorder characterised by an imperative desire to move the extremities associated with paraesthesias, motor restlessness, worsening of symptoms at rest in the evening or at night and, as a consequence, sleep disturbances particulary. Additionally, most patients with RLS have periodic limb movements during sleep and relaxed wakefulness. The aetiology of RLS remains unknown. Treatment of RLS is generally symptomatic, a causal therapy is possible only in the secondary forms. Dopaminergic agents including levodopa and dopamine agonists such as pergolide, pramipexole, cabergoline and ropinirole are regarded as the treatment of choice for idiopathic RLS, however, the development of augmentation of symptoms, especially under levodopa therapy, may be a major problem. Except in special circumstances, opioids and anticonvulsants such as gabapentin or benzodiazepines, are regarded as second-line treatment. In secondary RLS, the underlying illness should first be treated, although dopaminergic drugs may also be helpful.
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Affiliation(s)
- Thomas C Wetter
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, D-80804 Munich, Germany.
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44
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Chapter 18 Arousal parasomnias. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1567-4231(09)70043-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Abstract
Restless legs syndrome (RLS) was first described in 1672 but it is only recently that this disorder has attracted attention in defining its phenotype, and identifying its aetiology, pathogenesis and pharmacological treatment. RLS can be divided into primary (idiopathic) and secondary forms. RLS is common, affecting 5-15% of the total population and manifesting at any age from childhood to late adulthood. Prevalence tends to increase with patient age and there may be geographic variation. There is a clear genetic contribution to primary RLS and evidence for dopaminergic dysfunction. Although not all patients with RLS require medication, there can be a substantial reduction in the patient's quality of life related to pain, poor sleep and excessive daytime sleepiness. A variety of medications are now available for the symptomatic treatment of RLS. Dopaminergic therapy is currently the treatment of choice, usually initiated with a long-acting dopamine agonist, thereby avoiding some of the complications associated with levodopa. Anticonvulsants may be used as second-line treatment. Levodopa should be reserved for those patients who fail to respond to alternative medications because of the high risk of inducing augmentation. Hypnosedatives also have a role in RLS management. Patients with intractable RLS may require combination treatment. Several systemic disorders can cause RLS, and these should be identified and treated appropriately.
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Affiliation(s)
- Anthony H V Schapira
- University Department of Clinical Neurosciences, Royal Free and University College Medical School, London, UK.
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Chen S, Ondo WG, Rao S, Li L, Chen Q, Wang Q. Genomewide linkage scan identifies a novel susceptibility locus for restless legs syndrome on chromosome 9p. Am J Hum Genet 2004; 74:876-85. [PMID: 15077200 PMCID: PMC1181982 DOI: 10.1086/420772] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Accepted: 02/20/2004] [Indexed: 01/10/2023] Open
Abstract
Restless legs syndrome (RLS) is a common neurological disorder that affects 5%-12% of all whites. To genetically dissect this complex disease, we characterized 15 large and extended multiplex pedigrees, consisting of 453 subjects (134 affected with RLS). A familial aggregation analysis was performed, and SAGE FCOR was used to quantify the total genetic contribution in these families. A weighted average correlation of 0.17 between first-degree relatives was obtained, and heritability was estimated to be 0.60 for all types of relative pairs, indicating that RLS is a highly heritable trait in this ascertained cohort. A genomewide linkage scan, which involved >400 10-cM-spaced markers and spanned the entire human genome, was then performed for 144 individuals in the cohort. Model-free linkage analysis identified one novel significant RLS-susceptibility locus on chromosome 9p24-22 with a multipoint nonparametric linkage (NPL) score of 3.22. Suggestive evidence of linkage was found on chromosome 3q26.31 (NPL score 2.03), chromosome 4q31.21 (NPL score 2.28), chromosome 5p13.3 (NPL score 2.68), and chromosome 6p22.3 (NPL score 2.06). Model-based linkage analysis, with the assumption of an autosomal-dominant mode of inheritance, validated the 9p24-22 linkage to RLS in two families (two-point LOD score of 3.77; multipoint LOD score of 3.91). Further fine mapping confirmed the linkage result and defined this novel RLS disease locus to a critical interval. This study establishes RLS as a highly heritable trait, identifies a novel genetic locus for RLS, and will facilitate further cloning and identification of the genes for RLS.
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Affiliation(s)
- Shenghan Chen
- Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute, and Center for Cardiovascular Genetics and Cole Eye Institute, The Cleveland Clinic Foundation, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland; and Department of Neurology, Baylor College of Medicine, Houston
| | - William G. Ondo
- Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute, and Center for Cardiovascular Genetics and Cole Eye Institute, The Cleveland Clinic Foundation, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland; and Department of Neurology, Baylor College of Medicine, Houston
| | - Shaoqi Rao
- Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute, and Center for Cardiovascular Genetics and Cole Eye Institute, The Cleveland Clinic Foundation, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland; and Department of Neurology, Baylor College of Medicine, Houston
| | - Lin Li
- Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute, and Center for Cardiovascular Genetics and Cole Eye Institute, The Cleveland Clinic Foundation, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland; and Department of Neurology, Baylor College of Medicine, Houston
| | - Qiuyun Chen
- Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute, and Center for Cardiovascular Genetics and Cole Eye Institute, The Cleveland Clinic Foundation, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland; and Department of Neurology, Baylor College of Medicine, Houston
| | - Qing Wang
- Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute, and Center for Cardiovascular Genetics and Cole Eye Institute, The Cleveland Clinic Foundation, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland; and Department of Neurology, Baylor College of Medicine, Houston
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Tan EK, Ho SC, Eng P, Loh LM, Koh L, Lum SY, Teoh ML, Yih Y, Khoo D. Restless legs symptoms in thyroid disorders. Parkinsonism Relat Disord 2004; 10:149-51. [PMID: 15036169 DOI: 10.1016/j.parkreldis.2003.11.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2003] [Revised: 11/20/2003] [Accepted: 11/25/2003] [Indexed: 11/28/2022]
Abstract
Dopaminergic dysfunction is associated with thyroid disorders and restless legs syndrome (RLS). In a 'face-to-face' interview, we evaluated for RLS using the diagnostic criteria of the International Restless Legs Syndrome Study Group (IRLSSG) in patients diagnosed biochemically with either hyper- or hypothyroidism, and in controls without thyroid disorders. Amongst 146 consecutive patients with biochemically confirmed thyroid disorders, none satisfied all the IRLSSG criteria of RLS, similar to the control population (0.2%, 1/434). However, we found 8.2% (12/146) with RLS-like symptoms (satisfied the first 3 IRLSSG criteria) compared to 0.9% (4/434) in the controls (p < 0.0001). Four (33.3%) of these patients reported complete resolution of these symptoms after treatment for their thyroid condition. In conclusion, while RLS-like symptoms were observed in some patients with thyroid disorders, our study demonstrates no significant difference of RLS prevalence between patients with thyroid disorders and euthyroid controls.
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Affiliation(s)
- E K Tan
- Department of Neurology, Division of Medicine, Singapore General Hospital, Outram Road, Singapore, Singapore 169608.
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Abstract
Neurologic disorders may present or masquerade as pediatric sleep problems and fool the pediatrician, which may delay diagnosis and treatment. Many of the sleep problems in children with neurologic disorders arise directly from primary dysfunction or delayed maturation of their sleep-wake regulation systems. It is important to realize that nocturnal frontal lobe seizures or cluster headaches can be mistaken for night terrors, and craniopharyngiomas or myotonic dystrophy may present as narcolepsy-cataplexy. Hypothalamic dysfunction may explain not only the impaired circadian rhythm disorders in children with profound mental retardation but also excessive sleepiness and hyperphagia in Prader-Willi and Kleine-Levin syndromes. Intellectually challenged children perform better, learn more, and are better behaved with sufficient restorative sleep.
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Affiliation(s)
- Madeleine Grigg-Damberger
- Department of Neurology, University of New Mexico School of Medicine, MSC10 5620, Albuquerque, NM 87131-0001, USA.
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Allen RP, Picchietti D, Hening WA, Trenkwalder C, Walters AS, Montplaisi J. Restless legs syndrome: diagnostic criteria, special considerations, and epidemiology. A report from the restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med 2004; 4:101-19. [PMID: 14592341 DOI: 10.1016/s1389-9457(03)00010-8] [Citation(s) in RCA: 2023] [Impact Index Per Article: 101.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Restless legs syndrome is a common yet frequently undiagnosed sensorimotor disorder. In 1995, the International Restless Legs Syndrome Study Group developed standardized criteria for the diagnosis of restless legs syndrome. Since that time, additional scientific scrutiny and clinical experience have led to a better understanding of the condition. Modification of the criteria is now necessary to better reflect that increased body of knowledge, as well as to clarify slight confusion with the wording of the original criteria. SETTING The restless legs syndrome diagnostic criteria and epidemiology workshop at the National Institutes of Health. PARTICIPANTS Members of the International Restless Legs Syndrome Study Group and authorities on epidemiology and the design of questionnaires and scales. OBJECTIVE To modify the current criteria for the diagnosis of restless legs syndrome, to develop new criteria for the diagnosis of restless legs syndrome in the cognitively impaired elderly and in children, to create standardized criteria for the identification of augmentation, and to establish consistent questions for use in epidemiology studies. RESULTS The essential diagnostic criteria for restless legs syndrome were developed and approved by workshop participants and the executive committee of the International Restless Legs Syndrome Study Group. Criteria were also developed and approved for the additional aforementioned groups.
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Affiliation(s)
- Richard P Allen
- Department of Neurology, Sleep Medicine, Johns Hopkins Bayview Medical Center, Asthma and Allergy Building 1B46b, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
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Affiliation(s)
- J Winkelmann
- Department of Neurology, Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany.
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