1
|
Louis ED, Berry D, Ghanem A, Cosentino SA. Conversion Rate of Essential Tremor to Essential Tremor Parkinson Disease: Data From a Prospective Longitudinal Study. Neurol Clin Pract 2023; 13:e200162. [PMID: 37256209 PMCID: PMC10226077 DOI: 10.1212/cpj.0000000000200162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/02/2023] [Indexed: 06/01/2023]
Abstract
Background and Objectives There has been a long-standing dialog as to whether essential tremor (ET) increases the risk of developing Parkinson disease (PD). While there are relevant cross-sectional data, there are almost no longitudinal prospective data. We quantified the conversion rate from ET to ETPD in a prospective longitudinal cohort study of patients with ET. We compared the observed rate with that reported in the epidemiologic literature. Methods We enrolled patients with ET in a prospective, longitudinal study. A senior movement disorders neurologist evaluated standardized neurologic examinations every 18 months. Results One hundred ninety-three patients with ET (mean age = 78.1 ± 9.6 years, range = 55-96) had a mean follow-up duration of 4.1 years. Seven (3.6%) converted from ET to ETPD. The incidence of PD among patients with ET was 7/792.9 person-years (py; i.e., 882.8/100,000 py). A meta-analysis of the incidence (per 100,000 py) of PD in 14 studies from 13 countries across 4 continents reported an incidence of PD = 61.21 (men, 40 years or older) and 37.55 (women, 40 years or older). The incidence/100,000 py in men peaked in the 80- to 89-year-old age group (258.47) and in women in the 80- to 89-year-old age group (103.48 py). The abovementioned published values are 3.4-23.5 times lower than the value we observed for ET. Discussion The incidence of PD in an ET cohort is substantially higher than that reported in historical population-based control groups across numerous countries. Additional prospective longitudinal data are needed to further explore this association.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology (EDL, DB, AG), University of Texas Southwestern Medical Center, Dallas, TX; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (SAC), G.H. Sergiesvky Center, and Department of Neurology, Columbia University Irving Medical Center, New York
| | - Diane Berry
- Department of Neurology (EDL, DB, AG), University of Texas Southwestern Medical Center, Dallas, TX; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (SAC), G.H. Sergiesvky Center, and Department of Neurology, Columbia University Irving Medical Center, New York
| | - Ali Ghanem
- Department of Neurology (EDL, DB, AG), University of Texas Southwestern Medical Center, Dallas, TX; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (SAC), G.H. Sergiesvky Center, and Department of Neurology, Columbia University Irving Medical Center, New York
| | - Stephanie A Cosentino
- Department of Neurology (EDL, DB, AG), University of Texas Southwestern Medical Center, Dallas, TX; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (SAC), G.H. Sergiesvky Center, and Department of Neurology, Columbia University Irving Medical Center, New York
| |
Collapse
|
2
|
Louis ED, Faust PL. Prevalence of Lewy pathology in essential tremor is twice as high as expected: A plausible explanation for the enhanced risk for Parkinson disease seen in essential tremor cases. J Neuropathol Exp Neurol 2023; 82:454-455. [PMID: 36943259 PMCID: PMC10117153 DOI: 10.1093/jnen/nlad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Affiliation(s)
- Elan D Louis
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, New York, USA
| |
Collapse
|
3
|
Louis ED, Iglesias-Hernandez D, Hernandez NC, Flowers X, Kuo SH, Vonsattel JPG, Faust PL. Characterizing Lewy Pathology in 231 Essential Tremor Brains From the Essential Tremor Centralized Brain Repository. J Neuropathol Exp Neurol 2022; 81:796-806. [PMID: 35950950 PMCID: PMC9487643 DOI: 10.1093/jnen/nlac068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Essential Tremor Centralized Brain Repository is the largest repository of prospectively collected essential tremor (ET) brains (n = 231). Hence, we are uniquely poised to address several questions: What proportion of ET cases has Lewy pathology (LP)? What is the nature of that pathology and how does it relate to other comorbidities? Each brain had a complete neuropathological assessment, including α-synuclein immunostaining. We created a 10-category classification scheme to fully encapsulate the patterns of LP observed. Four metrics of cerebellar pathology were also quantified. Mean age at death = 89.0 ± 6.4 years. Fifty-eight (25.1%) had LP and 46 (19.9%) had early to late stages of Parkinson disease (PD). LP was very heterogeneous. Of 58 cases with LP, 14 (24.1%) clinically developed possible PD or PD after a latency of 5 or more years. There was a similar degree of cerebellar pathology in ET cases both with and without LP. In summary, 1 in 4 ET cases had LP-a proportion that seems higher than expected based on studies among control populations. Heterogeneous LP likely reflects clinical associations between ET and PD, and ET with Alzheimer disease-type neuropathology. These data further our understanding of ET and its relatedness to other degenerative diseases.
Collapse
Affiliation(s)
- Elan D Louis
- From the Department of Neurology, University of Texas Southwestern, Dallas, Texas, USA
| | | | - Nora C Hernandez
- From the Department of Neurology, University of Texas Southwestern, Dallas, Texas, USA
| | - Xena Flowers
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, USA
| | - Sheng-Han Kuo
- Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Jean Paul G Vonsattel
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, New York, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, New York, USA
| |
Collapse
|
4
|
Cho HJ. Is essential tremor a degenerative or an electrical disorder? Electrical disorder. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:103-128. [PMID: 35750360 DOI: 10.1016/bs.irn.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Essential tremor (ET) is one of the most common movement disorders, yet we do not have a complete understanding of its pathophysiology. From a phenomenology standpoint, ET is an isolated tremor syndrome of bilateral upper limb action tremor with or without tremor in other body locations. ET is a pathological tremor that arises from excessive oscillation in the central motor network. The tremor network comprises of multiple brain regions including the inferior olive, cerebellum, thalamus, and motor cortex, and there is evidence that a dynamic oscillatory disturbance within this network leads to tremor. ET is a chronic disorder, and the natural history shows a slow progression of tremor intensity with age. There are reported data suggesting that ET follows the disease model of a neurodegenerative disorder, however whether ET is a degenerative or electrical disorder has been a subject of debate. In this chapter, we will review cumulative evidence that ET as a syndrome is a fundamentally electric disorder. The etiology is likely heterogenous and may not be primarily neurodegenerative.
Collapse
Affiliation(s)
- Hyun Joo Cho
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
| |
Collapse
|
5
|
Louis ED, Hernandez NC, Ottman R, Clark LN. Mixed Motor Disorder: Essential Tremor Families With Heterogeneous Motor Phenomenology. Neurol Clin Pract 2022; 11:e817-e825. [PMID: 34992964 DOI: 10.1212/cpj.0000000000001100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 04/09/2021] [Indexed: 11/15/2022]
Abstract
Background and Objectives Essential tremor (ET) is one of the most prevalent movement disorders. Because ET is so common, individuals with other neurologic disorders may also have ET. There is evidence, however, that the cooccurrence of ET with Parkinson disease (PD) and/or dystonia is not merely a chance cooccurrence. We have observed combinations of these 3 movement disorders within individuals and across individuals within families containing multiple individuals with ET. This observation has a number of implications. Our objective is to present 4 ET families in whom motor phenomenology was heterogeneous and discuss the implications of this finding. Methods ET cases and their relatives were enrolled in the Family Study of Essential Tremor (2015-present). Phenotyping was performed by a senior movement disorders neurologist based on neurologic examination. Results We present 4 families, including 14 affected individuals, among whom assigned diagnoses were ET, PD, ET + PD, and ET + dystonia. In those with ET and another movement disorder, the predominant and earliest phenotype was ET. Discussion There are assortments of these 3 involuntary motor disorders, ET, dystonia, and PD, both within individuals and in different individuals within ET families. This observation has mechanistic implications. Furthermore, we believe that the concept of the mixed motor disorder should enter into and inform the clinical dialogue. In assigning diagnoses, clinicians are swayed by family history information, and they should be prepared to observe a mix of different motor disorders to manifest within particular families.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology (EDL, NCH), University of Texas Southwestern, Dallas; G.H. Sergievsky Center (RO), Department of Neurology (RO), College of Physicians and Surgeons, and Department of Epidemiology (RO), Mailman School of Public Health, Columbia University; Division of Translational Epidemiology (RO), New York State Psychiatric Institute; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (LNC), College of Physicians and Surgeons, Columbia University, New York
| | - Nora C Hernandez
- Department of Neurology (EDL, NCH), University of Texas Southwestern, Dallas; G.H. Sergievsky Center (RO), Department of Neurology (RO), College of Physicians and Surgeons, and Department of Epidemiology (RO), Mailman School of Public Health, Columbia University; Division of Translational Epidemiology (RO), New York State Psychiatric Institute; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (LNC), College of Physicians and Surgeons, Columbia University, New York
| | - Ruth Ottman
- Department of Neurology (EDL, NCH), University of Texas Southwestern, Dallas; G.H. Sergievsky Center (RO), Department of Neurology (RO), College of Physicians and Surgeons, and Department of Epidemiology (RO), Mailman School of Public Health, Columbia University; Division of Translational Epidemiology (RO), New York State Psychiatric Institute; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (LNC), College of Physicians and Surgeons, Columbia University, New York
| | - Lorraine N Clark
- Department of Neurology (EDL, NCH), University of Texas Southwestern, Dallas; G.H. Sergievsky Center (RO), Department of Neurology (RO), College of Physicians and Surgeons, and Department of Epidemiology (RO), Mailman School of Public Health, Columbia University; Division of Translational Epidemiology (RO), New York State Psychiatric Institute; and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (LNC), College of Physicians and Surgeons, Columbia University, New York
| |
Collapse
|
6
|
Parkinsonism and tremor syndromes. J Neurol Sci 2021; 433:120018. [PMID: 34686357 DOI: 10.1016/j.jns.2021.120018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/06/2021] [Accepted: 09/29/2021] [Indexed: 01/22/2023]
Abstract
Tremor, the most common movement disorder, may occur in isolation or may co-exist with a variety of other neurologic and movement disorders including parkinsonism, dystonia, and ataxia. When associated with Parkinson's disease, tremor may be present at rest or as an action tremor overlapping in phenomenology with essential tremor. Essential tremor may be associated not only with parkinsonism but other neurological disorders, suggesting the possibility of essential tremor subtypes. Besides Parkinson's disease, tremor can be an important feature of other parkinsonian disorders, such as atypical parkinsonism and drug-induced parkinsonism. In addition, tremor can be a prominent feature in patients with other movement disorders such as fragile X-associated tremor/ataxia syndrome, and Wilson's disease in which parkinsonian features may be present. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.
Collapse
|
7
|
Tarakad A, Jankovic J. Essential Tremor and Parkinson's Disease: Exploring the Relationship. Tremor Other Hyperkinet Mov (N Y) 2019; 8:589. [PMID: 30643667 PMCID: PMC6329774 DOI: 10.7916/d8md0gvr] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/04/2018] [Indexed: 12/31/2022] Open
Abstract
Background There is longstanding controversy surrounding the possible link between essential tremor (ET) and Parkinson's disease (PD). Inconsistent and unreliable diagnostic criteria may in part account for some of the difficulties in defining the relationship between these two common movement disorders. Methods References for this systematic review were identified using PubMed with the search terms "essential tremor" AND "Parkinson's disease" with articles published in English between 1960 and September 2018 included. Results In this review we provide evidence that some patients diagnosed with ET have an increased risk of developing PD years or decades after onset of action tremor. There are several still unresolved questions about the link between the two disorders including lack of verifiable diagnostic criteria for the two disorders and marked overlap in phenomenology. Here we review clinical, epidemiologic, imaging, pathologic, and genetic studies that address the ET-PD relationship. Several lines of evidence support the association between ET and PD, including overlapping motor and non-motor features, relatively high prevalence of rapid eye movement sleep behavior disorder (26-43%) in ET patients, increased prevalence of PD in patients with longstanding antecedent ET, increased prevalence of ET in family members of patients with PD, and the presence of Lewy bodies in the brains of some ET patients (15-24%). Discussion There is a substantial body of evidence supporting the association between ET and PD within at least a subset of patients, although the nature and possible pathogenic mechanisms of the relationship are not well understood.
Collapse
Affiliation(s)
- Arjun Tarakad
- Parkinson’s Disease Center and Movement Disorders Clinic, Baylor College of Medicine Houston, TX, USA
| | - Joseph Jankovic
- Parkinson’s Disease Center and Movement Disorders Clinic, Baylor College of Medicine Houston, TX, USA
| |
Collapse
|
8
|
Arabia G, Lupo A, Manfredini LI, Vescio B, Nisticò R, Barbagallo G, Salsone M, Morelli M, Novellino F, Nicoletti G, Quattrone A, Cascini GL, Louis ED, Quattrone A. Clinical, electrophysiological, and imaging study in essential tremor-Parkinson's disease syndrome. Parkinsonism Relat Disord 2018; 56:20-26. [PMID: 29885986 DOI: 10.1016/j.parkreldis.2018.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 05/17/2018] [Accepted: 06/03/2018] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Essential tremor-Parkinson's disease (ET-PD) syndrome is a clinical condition in which individuals with a long-lasting history of Essential tremor (ET) eventually develop Parkinson's disease (PD). The aim of the study was to investigate the accuracy performances of clinical, neurophysiological, and imaging biomarkers in differentiating patients affected by ET-PD syndrome from patients with ET or PD. METHODS Nineteen patients affected by ET-PD syndrome, 48 ET patients, and 37 tremor-dominant PD (t-PD) patients were included. Electrophysiological studies, including blink-reflex recovery cycle and tremor parameters analyses, were performed in all groups. Nigro-striatal and cardiac sympathetic denervation were also investigated. Sensitivity, specificity and accuracy of clinical, electrophysiological, and radiological features in differentiating ET-PD syndrome from ET and PD were calculated. RESULTS ET-PD patients had significantly lower rigidity (p = 0.007) and higher postural/kinetic tremor (p = 0.007) scores, in comparison to t-PD patients. ET-PD patients, differently from PD patients, had a synchronous pattern of resting tremor and, differently from ET patients, had abnormal blink-reflex recovery cycle. ET-PD patients also showed reduced nigro-striatal and cardiac sympathetic uptakes, albeit to a lesser extent than in PD patients. The highest accuracy values were found for the synchronous pattern of resting tremor (97.1%) in distinguishing ET-PD from PD, and for presence of abnormal blink-recovery cycle (100%) in distinguishing ET-PD syndrome from ET. CONCLUSION Our study demonstrates that some electrophysiological parameters, such as a synchronous resting tremor pattern and the abnormal blink-recovery cycle were the most accurate biomarkers in distinguishing patient with ET-PD syndrome from those with ET or those with PD.
Collapse
Affiliation(s)
- Gennarina Arabia
- Institute of Neurology, Department of Medical Sciences, University "Magna Graecia" of Catanzaro, Italy
| | - Angela Lupo
- Institute of Neurology, Department of Medical Sciences, University "Magna Graecia" of Catanzaro, Italy
| | - Lucia Ilaria Manfredini
- Institute of Neurology, Department of Medical Sciences, University "Magna Graecia" of Catanzaro, Italy
| | | | - Rita Nisticò
- Neuroimaging Research Unit, IBFM, National Research Council, Catanzaro, Italy
| | - Gaetano Barbagallo
- Institute of Neurology, Department of Medical Sciences, University "Magna Graecia" of Catanzaro, Italy
| | - Maria Salsone
- Neuroimaging Research Unit, IBFM, National Research Council, Catanzaro, Italy
| | - Maurizio Morelli
- Institute of Neurology, Department of Medical Sciences, University "Magna Graecia" of Catanzaro, Italy
| | - Fabiana Novellino
- Neuroimaging Research Unit, IBFM, National Research Council, Catanzaro, Italy
| | - Giuseppe Nicoletti
- Neuroimaging Research Unit, IBFM, National Research Council, Catanzaro, Italy
| | - Andrea Quattrone
- Institute of Neurology, Department of Medical Sciences, University "Magna Graecia" of Catanzaro, Italy
| | | | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Aldo Quattrone
- Neuroimaging Research Unit, IBFM, National Research Council, Catanzaro, Italy; Neuroscience Center, University "Magna Graecia" of Catanzaro, Italy.
| |
Collapse
|
9
|
rs3851179 Polymorphism at 5' to the PICALM Gene is Associated with Alzheimer and Parkinson Diseases in Brazilian Population. Neuromolecular Med 2017; 19:293-299. [PMID: 28567584 DOI: 10.1007/s12017-017-8444-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 05/19/2017] [Indexed: 12/17/2022]
Abstract
Alzheimer's (AD) and Parkinson's diseases (PD) share clinical and pathological features, suggesting that they could have common pathogenic mechanisms, as well as overlapping genetic modifiers. Here, we performed a case-control study in a Brazilian population to clarify whether the risk of AD and PD might be influenced by shared polymorphisms at PICALM (rs3851179), CR1 (rs6656401) and CLU (rs11136000) genes, which were previously identified as AD risk factors by genome-wide association studies. For this purpose, 174 late-onset AD patients, 166 PD patients and 176 matched controls were genotyped using TaqMan® assays. The results revealed that there were significant differences in genotype and allele frequencies for the SNP PICALM rs3851179 between AD/PD cases and controls, but none for CR1 rs6656401 and CLU rs11136000 intronic polymorphisms. After stratification by APOE ε4 status, the protective effect of the PICALM rs3851179 A allele in AD cases remains evident only in APOE ε4 (-) carriers, suggesting that the APOE ε4 risky allele weakens its protective effect in the APOE ε4 (+) subgroup. More genetic studies using large-sized and well-defined matched samples of AD and PD patients from mixed populations as well as functional correlation analysis are urgently needed to clarify the role of rs3851179 in the AD/PD risk. An understanding of the contribution of rs3851179 to the development of AD and PD could provide new targets for the development of novel therapies.
Collapse
|
10
|
Malek N, Swallow DMA, Grosset KA, Lawton MA, Marrinan SL, Lehn AC, Bresner C, Bajaj N, Barker RA, Ben-Shlomo Y, Burn DJ, Foltynie T, Hardy J, Morris HR, Williams NM, Wood N, Grosset DG. Tracking Parkinson's: Study Design and Baseline Patient Data. JOURNAL OF PARKINSONS DISEASE 2016; 5:947-59. [PMID: 26485428 PMCID: PMC4927877 DOI: 10.3233/jpd-150662] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background: There is wide variation in the phenotypic expression of Parkinson’s disease (PD), which is driven by both genetic and epidemiological influences. Objectives: To define and explain variation in the clinical phenotype of PD, in relation to genotypic variation. Methods: Tracking Parkinson’s is a multicentre prospective longitudinal epidemiologic and biomarker study of PD. Patients attending specialist clinics in the United Kingdom with recent onset (<3.5 years) and young onset (diagnosed <50 years of age) PD were enrolled. Motor, non-motor and quality of life assessments were performed using validated scales. Cases are followed up 6 monthly up to 4.5 years for recent onset PD, and up to 1 year for young onset PD. We present here baseline clinical data from this large and demographically representative cohort. Results: 2247 PD cases were recruited (1987 recent onset, 260 young onset). Recent onset cases had a mean (standard deviation, SD) age of 67.6 years (9.3) at study entry, 65.7% males, with disease duration 1.3 years (0.9), MDS-UPDRS 3 scores 22.9 (12.3), LEDD 295 mg/day (211) and PDQ-8 score 5.9 (4.8). Young onset cases were 53.5 years old (7.8) at study entry, 66.9% male, with disease duration 10.2 years (6.7), MDS-UPDRS 3 scores 27.4 (15.3), LEDD 926 mg/day (567) and PDQ-8 score 11.6 (6.1). Conclusions: We have established a large clinical PD cohort, consisting of young onset and recent onset cases, which is designed to evaluate variation in clinical expression, in relation to genetic influences, and which offers a platform for future imaging and biomarker research.
Collapse
Affiliation(s)
- Naveed Malek
- Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
| | - Diane M A Swallow
- Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
| | - Katherine A Grosset
- Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
| | - Michael A Lawton
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Sarah L Marrinan
- Institute of Neuroscience, University of Newcastle, Newcastle upon Tyne, UK
| | - Alexander C Lehn
- Institute of Neuroscience, University of Newcastle, Newcastle upon Tyne, UK
| | - Catherine Bresner
- Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Nin Bajaj
- Department of Neurology, Queen's Medical Centre, Nottingham, UK
| | - Roger A Barker
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, Cambridge, UK
| | - Yoav Ben-Shlomo
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - David J Burn
- Institute of Neuroscience, University of Newcastle, Newcastle upon Tyne, UK
| | - Thomas Foltynie
- Sobell Department of Motor Neuroscience, UCL Institute of Neurology, London, UK
| | - John Hardy
- Reta Lila Weston Laboratories, Dept of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Huw R Morris
- Department of Clinical Neuroscience, UCL Institute of Neurology, London, UK
| | - Nigel M Williams
- Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Nicholas Wood
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Donald G Grosset
- Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
| | | |
Collapse
|
11
|
Louis ED, Clark L, Ottman R. Familial Aggregation and Co-Aggregation of Essential Tremor and Parkinson's Disease. Neuroepidemiology 2015; 46:31-6. [PMID: 26606512 DOI: 10.1159/000442021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/25/2015] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Current data suggest that the 2 common tremor disorders, essential tremor (ET) and Parkinson's disease (PD), may be associated with one another. Familial aggregation studies allow one to further explore their relatedness. METHODS Probands with ET (n = 110), PD (n = 130) or both ET and PD (n = 27) and control probands (n = 177) reported whether they had relatives with these diseases or with non-specific tremor. RESULTS A greater proportion of ET probands than control probands reported relatives with ET (30.0 vs. 2.8%, p < 0.001), non-specific tremor (38.2 vs. 13.6%, p < 0.001) and both ET and PD in different relatives (6.4 vs. 0.6%, p = 0.004). A greater proportion of PD probands than control probands reported relatives with PD (20.0 vs. 8.5%, p = 0.003), ET (11.5 vs. 2.8%, p = 0.002) and both ET and PD in different relatives (6.9 vs. 0.6%, p = 0.002). CONCLUSIONS This study provides evidence for the aggregation of ET in ET families and PD in PD families, and the familial co-aggregation of ET and PD.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Conn., USA
| | | | | |
Collapse
|
12
|
Béliveau E, Tremblay C, Aubry-Lafontaine É, Paris-Robidas S, Delay C, Robinson C, Ferguson L, Rajput AH, Rajput A, Calon F. Accumulation of amyloid-β in the cerebellar cortex of essential tremor patients. Neurobiol Dis 2015; 82:397-408. [PMID: 26253607 DOI: 10.1016/j.nbd.2015.07.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 07/24/2015] [Accepted: 07/31/2015] [Indexed: 12/31/2022] Open
Abstract
The accumulation of insoluble amyloid-beta (Aβ) peptides is associated with neurodegenerative disorders, such as Alzheimer's disease (AD). As essential tremor (ET) could involve neurodegenerative processes in the cerebellum, we quantified soluble and insoluble Aβ in cerebellar cortices from patients diagnosed with ET (n=9), compared to Controls (n=16) or individuals with Parkinson's disease (n=10). Although ante-mortem cognitive performance was not documented, all individuals included had the diagnosis of AD ruled out by a neuropathologist. ELISA-determined concentrations of insoluble Aβ42 in ET patients displayed a bimodal distribution, with a median 246-fold higher than in Controls (P<0.01, Kruskal-Wallis). Higher Aβ42 concentrations were measured in the parietal cortex of the same ET patients, compared to Controls (107-fold median increase, P<0.01, Kruskal-Wallis), but similar phosphorylated tau levels were detected. The rise in cerebellar insoluble Aβ42 concentrations is not associated to APP expression and processing or the ApoE4 status. However, Aβ42 levels in ET individuals were correlated with cerebellar insoluble phosphorylated tau (r(2)=0.71, P=0.005), unphosphorylated neurofilament heavy chain (NF-H; r(2)=0.50, P=0.030) and Lingo-1 (r(2)=0.73, P=0.007), indicative of a generalized neurodegenerative process involving the cerebellum. Our results suggest prevalent accumulations of insoluble Aβ42 in the cerebellum of ET, but not in age-matched PD. Whether this anomaly plays a role in ET symptoms warrants further investigations.
Collapse
Affiliation(s)
- Eric Béliveau
- Faculty of Pharmacy, Université Laval, Québec, QC, Canada; Neurosciences Axis, Centre de recherche du CHU de Québec, Québec, QC, Canada
| | - Cyntia Tremblay
- Faculty of Pharmacy, Université Laval, Québec, QC, Canada; Neurosciences Axis, Centre de recherche du CHU de Québec, Québec, QC, Canada
| | - Émilie Aubry-Lafontaine
- Faculty of Pharmacy, Université Laval, Québec, QC, Canada; Neurosciences Axis, Centre de recherche du CHU de Québec, Québec, QC, Canada
| | - Sarah Paris-Robidas
- Faculty of Pharmacy, Université Laval, Québec, QC, Canada; Neurosciences Axis, Centre de recherche du CHU de Québec, Québec, QC, Canada
| | | | - Chris Robinson
- Division of Neurology, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada
| | - Les Ferguson
- Division of Neurology, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ali H Rajput
- Division of Neurology, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada
| | - Alex Rajput
- Division of Neurology, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada
| | - Frédéric Calon
- Faculty of Pharmacy, Université Laval, Québec, QC, Canada; Neurosciences Axis, Centre de recherche du CHU de Québec, Québec, QC, Canada.
| |
Collapse
|
13
|
Feldman AL, Wirdefeldt K, Johansson ALV, Gatz M, Pedersen NL. Evidence for modest familial co-aggregation between dementia and parkinsonism. Eur J Epidemiol 2013; 29:49-56. [PMID: 24248476 DOI: 10.1007/s10654-013-9864-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 11/06/2013] [Indexed: 11/25/2022]
Abstract
To investigate the contribution of shared familial risk to the co-occurrence of dementia and parkinsonism by studying familial co-aggregation of Alzheimer's disease (AD) and Parkinson's disease (PD). Using Swedish population-based registers we constructed two cohorts; a first-degree relative cohort of persons born 1932-1960 (n = 2,775,332) and a spouse cohort of persons born 1890-1960 (n = 4,736,006). Study persons were followed up between 1969 and 2009 in the National Patient and Cause of Death Registers. We modeled the association between incidence of disease and having at least one affected relative using Cox proportional hazard regression that estimated hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for age, sex and number of relatives. Within each disorder; dementia, AD, parkinsonian disorders and PD, there was a strong association between risk of disease and having at least one affected sibling or parent. There was also a modest shared familial risk between the diseases; risk of parkinsonian disorders was associated with having a sibling with AD (HR 1.35, 95% CI 1.11-1.65) and risk of dementia was associated with having a sibling with PD (HR 1.20, 95% CI 1.02-1.41). There were no meaningful familial risks among spouses. The risk of co-occurring dementia in PD was considerably increased (HR 2.83, 95% CI 2.76-2.89). There is strong familial aggregation within dementia, AD, parkinsonian disorders and PD, and modest familial co-aggregation between dementia and parkinsonism. Thus, co-occurrence of dementia and parkinsonism is not primarily caused by shared familial risk between AD and PD.
Collapse
Affiliation(s)
- Adina L Feldman
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, PO-Box 281, 17177, Stockholm, Sweden,
| | | | | | | | | |
Collapse
|
14
|
Testa CM. Key issues in essential tremor genetics research: Where are we now and how can we move forward? TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2013; 3. [PMID: 23450143 PMCID: PMC3582856 DOI: 10.7916/d8q23z0z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 12/04/2012] [Indexed: 01/06/2023]
Abstract
Background Genetics research is an avenue towards understanding essential tremor (ET). Advances have been made in genetic linkage and association: there are three reported ET susceptibility loci, and mixed but growing data on risk associations. However, causal mutations have not been forthcoming. This disappointing lack of progress has opened productive discussions on challenges in ET and specifically ET genetics research, including fundamental assumptions in the field. Methods This article reviews the ET genetics literature, results to date, the open questions in ET genetics and the current challenges in addressing them. Results Several inherent ET features complicate genetic linkage and association studies: high potential phenocopy rates, inaccurate tremor self-reporting, and ET misdiagnoses are examples. Increasing use of direct examination data for subjects, family members, and controls is one current response. Smaller moves towards expanding ET phenotype research concepts into non-tremor features, clinically disputed ET subsets, and testing phenotype features instead of clinical diagnosis against genetic data are gradually occurring. The field has already moved to considering complex trait mechanisms requiring detection of combinations of rare genetic variants. Hypotheses may move further to consider novel mechanisms of inheritance, such as epigenetics. Discussion It is an exciting time in ET genetics as investigators start moving past assumptions underlying both phenotype and genetics experimental contributions, overcoming challenges to collaboration, and engaging the ET community. Multicenter collaborative efforts comprising rich longitudinal prospective phenotype data and neuropathologic analysis combined with the latest in genetics experimental design and technology will be the next wave in the field.
Collapse
Affiliation(s)
- Claudia M Testa
- Virginia Commonwealth University, Parkinson's and Movement Disorders Center, Richmond Virginia, USA
| |
Collapse
|
15
|
Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E, Agúndez JAG. The relationship between Parkinson's disease and essential tremor: review of clinical, epidemiologic, genetic, neuroimaging and neuropathological data, and data on the presence of cardinal signs of parkinsonism in essential tremor. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2012; 2. [PMID: 23439992 PMCID: PMC3572635 DOI: 10.7916/d8fn14z6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/18/2012] [Indexed: 12/01/2022]
Abstract
BACKGROUND The possible relationship between essential tremor (ET) and Parkinson's disease (PD) has been controversial since the first description of PD. However, there is increasing evidence suggesting an overlap between these two disorders. The aim of this review is to examine the relationship between PD and ET, focusing on clinical, epidemiologic, genetic, neuroimaging, and neuropathological data, and the presence of cardinal parkinsonism symptoms in ET. METHODS We conducted a PubMed search for articles published between 1966 and November 2011 regarding the relationship between ET and PD and the presence of postural tremor in PD patients; the presence of rest tremor, rigidity, and slowed movements in ET patients is reviewed. RESULTS Clinical series, follow-up studies of ET patients, and case-control and genetic epidemiological studies indicate that ET is associated with increased risk for PD. Some neuroimaging studies and neuropathological reports suggest an association between the two diseases. ET patients show high prevalence of rest tremor, and at least seven studies described slowed movements (possibly related to cerebellar dysfunction and/or bradykinesia) in patients with ET. DISCUSSION There is reasonable epidemiological and clinical evidence to support a link between ET and PD, although it is not clear what factors predict ET patient risk for developing PD or, more rarely, of PD patients developing ET. Future multicentric and multidisciplinary studies including epidemiological, clinical, neuroimaging, genetic, and neuropathological assessments are required to understand these associations.
Collapse
|
16
|
Brüggemann N, Külper W, Hagenah J, Bauer P, Pattaro C, Tadic V, Lohnau T, Winkler S, Tönnies H, Sprenger A, Pramstaller P, Rolfs A, Siebert R, Riess O, Vieregge P, Lohmann K, Klein C. Autosomal dominant Parkinson's disease in a large German pedigree. Acta Neurol Scand 2012; 126:129-37. [PMID: 22107061 DOI: 10.1111/j.1600-0404.2011.01621.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE While several genes have been identified to cause Parkinson's disease (PD), monogenic forms explain only a small proportion of cases. We report clinical and genetic results in a large family with late-onset autosomal dominant PD. METHODS Thirty-eight family members of a five-generation Northern German PD family underwent a detailed neurologic examination, and transcranial sonography was performed in fifteen of them. Comprehensive mutation analysis of known PD-causing genes and a genome-wide linkage analysis were performed. RESULTS Late-onset definite PD was found in five subjects with a mean age at onset of 63 years. Another six individuals presented either with probable/possible PD or with subtle parkinsonian signs. Six members with a mean age of 79 years had an essential tremor phenotype. Mode of PD inheritance was compatible with autosomal dominant transmission. One of three examined patients with definite PD demonstrated an increased area of substantia nigra hyperechogenicity upon transcranial sonography. Comprehensive linkage and mutational analysis excluded mutations in known PD-causing genes. Genome-wide linkage analysis suggested a putative disease gene in an 11.3-Mb region on chromosome 7p15-21.1 with a multipoint LOD score of 2.0. CONCLUSIONS The findings in this family further demonstrate genetic heterogeneity in familial autosomal dominant late-onset PD.
Collapse
Affiliation(s)
- N Brüggemann
- Division of Clinical and Molecular Neurogenetics at the Department of Neurology, University of Lübeck, Lübeck, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Schapira AHV, Hillbom M. Publishing changes and information delivery in the clinical neurosciences. Eur J Neurol 2011. [DOI: 10.1111/j.1468-1331.2011.03594.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
18
|
Gao J, Huang X, Park Y, Hollenbeck A, Chen H. An exploratory study on CLU, CR1 and PICALM and Parkinson disease. PLoS One 2011; 6:e24211. [PMID: 21912625 PMCID: PMC3166161 DOI: 10.1371/journal.pone.0024211] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 08/08/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Recent GWAS and subsequent confirmation studies reported several single-nucleotide polymorphisms (SNPs) at the CLU, CR1 and PICALM loci in association with late-onset Alzheimer's disease (AD). Parkinson disease (PD) shares several clinical and pathologic characteristics with AD; we therefore explored whether these SNPs were also associated with PD risk. METHODOLOGY/PRINCIPAL FINDINGS 791 non-Hispanic Whites cases and 1,580 matched controls were included in the study. Odds ratios (OR) and 95% confidence intervals (CI) were obtained from logistic regression models. rs11136000 at the CLU locus was associated with PD risk under the recessive model (comparing TT versus CC+CT: OR = 0.71, 95% CI: 0.55-0.92, p = 0.008) after adjusting for year of birth, gender, smoking, and caffeine intake. Further adjustment for family history of PD and ApoE ε4 status did not change the result. In addition, we did not find evidence for effect modification by ApoE or known PD risk factors. The association, however, appeared to be stronger for PD with dementia (OR = 0.49, 95% CI: 0.27-0.91) than for PD without dementia (OR = 0.81, 95% CI: 0.61-1.06). The two other SNPs, rs6656401 from CR1, and rs3851179 from PICALM region were not associated with PD (p>0.05). CONCLUSION Our exploratory analysis suggests an association of CLU with PD. This exploratory finding and the role of dementia in explaining this finding needs further investigation.
Collapse
Affiliation(s)
- Jianjun Gao
- Epidemiology Branch of the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Xuemei Huang
- Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania, United States of America
| | - YikYung Park
- Nutritional Epidemiology Branch, National Cancer Institute, Rockville, Maryland, United States of America
| | | | - Honglei Chen
- Epidemiology Branch of the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| |
Collapse
|
19
|
Current World Literature. Curr Opin Neurol 2011; 24:409-13. [DOI: 10.1097/wco.0b013e3283499d51] [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]
|
20
|
LaRoia H, Louis ED. Association between essential tremor and other neurodegenerative diseases: what is the epidemiological evidence? Neuroepidemiology 2011; 37:1-10. [PMID: 21757958 DOI: 10.1159/000328866] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 04/27/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The possible links between essential tremor (ET) and Parkinson's disease (PD) and, more recently, between ET and Alzheimer's disease (AD) have been of great interest, particularly with the emergence of postmortem data suggesting that ET itself may be a neurodegenerative disease. Given the very high population prevalence of ET, its possible role as a risk factor for PD and AD is of special significance. At the center of this debate is the burgeoning evidence from epidemiological studies, examining whether there is an increased co-occurrence of these conditions within the same individuals or within families. METHODS We conducted a PubMed search from 1966 to March 2011 and reviewed the epidemiological evidence, restricting our analyses to studies that generated quantifiable measures of association (odds ratios or relative risks), thereby being able to assess the role of chance. RESULTS The most robust evidence, from case-control, prospective and familial aggregation studies, indicates that ET is associated with increased odds and increased risks of both PD and AD. CONCLUSIONS There is reasonable epidemiological evidence to support a link between ET and these neurodegenerative diseases. Further studies are needed to corroborate the current results, provide additional estimates of effect and begin to explore the mechanistic underpinnings for these intriguing associations.
Collapse
Affiliation(s)
- Hiral LaRoia
- Department of Neurology, Columbia University, New York, NY, USA
| | | |
Collapse
|
21
|
Puschmann A, Pfeiffer RF, Stoessl AJ, Kuriakose R, Lash JL, Searcy JA, Strongosky AJ, Vilariño-Güell C, Farrer MJ, Ross OA, Dickson DW, Wszolek ZK. A family with Parkinsonism, essential tremor, restless legs syndrome, and depression. Neurology 2011; 76:1623-30. [PMID: 21555728 DOI: 10.1212/wnl.0b013e318219fb42] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Previous epidemiologic and genetic studies have suggested a link between Parkinson disease (PD), essential tremor (ET), and restless legs syndrome (RLS). METHODS We describe the clinical, PET, and pathologic characteristics of an extensive kindred from Arkansas with hereditary PD, ET, and RLS. The pedigree contains 138 individuals. Sixty-five family members were examined neurologically up to 3 times from 2004 to 2010. Clinical data were collected from medical records and questionnaires. Genetic studies were performed. Five family members underwent multitracer PET. Two individuals with PD were examined postmortem. RESULTS Eleven family members had PD with generally mild and slowly progressive symptoms. Age at onset was between 39 and 74 years (mean 59.1, SD 13.4). All individuals treated with l-dopa responded positively. Postural or action tremor was present in 6 individuals with PD, and in 19 additional family members. Fifteen persons reported symptoms of RLS. PET showed reduced presynaptic dopamine function typical of sporadic PD in a patient with PD and ET, but not in persons with ET or RLS. The inheritance pattern was autosomal dominant for PD and RLS. No known pathogenic mutation in PD-related genes was found. Fourteen of the family members with PD, ET, or RLS had depression. Neuropathologic examination revealed pallidonigral pigment spheroid degeneration with ubiquitin-positive axonal spheroids, TDP43-positive pathology in the basal ganglia, hippocampus, and brainstem, and only sparse Lewy bodies. CONCLUSION Familial forms of PD, ET, RLS, and depression occur in this family. The genetic cause remains to be elucidated.
Collapse
Affiliation(s)
- A Puschmann
- Department of Neurology, Mayo Clinic Jacksonville, 4500 San Pablo Road, Jacksonville, FL 32224, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Wirdefeldt K, Adami HO, Cole P, Trichopoulos D, Mandel J. Epidemiology and etiology of Parkinson's disease: a review of the evidence. Eur J Epidemiol 2011; 26 Suppl 1:S1-58. [PMID: 21626386 DOI: 10.1007/s10654-011-9581-6] [Citation(s) in RCA: 724] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 04/05/2011] [Indexed: 12/14/2022]
Abstract
The etiology of Parkinson's disease (PD) is not well understood but likely to involve both genetic and environmental factors. Incidence and prevalence estimates vary to a large extent-at least partly due to methodological differences between studies-but are consistently higher in men than in women. Several genes that cause familial as well as sporadic PD have been identified and familial aggregation studies support a genetic component. Despite a vast literature on lifestyle and environmental possible risk or protection factors, consistent findings are few. There is compelling evidence for protective effects of smoking and coffee, but the biologic mechanisms for these possibly causal relations are poorly understood. Uric acid also seems to be associated with lower PD risk. Evidence that one or several pesticides increase PD risk is suggestive but further research is needed to identify specific compounds that may play a causal role. Evidence is limited on the role of metals, other chemicals and magnetic fields. Important methodological limitations include crude classification of exposure, low frequency and intensity of exposure, inadequate sample size, potential for confounding, retrospective study designs and lack of consistent diagnostic criteria for PD. Studies that assessed possible shared etiological components between PD and other diseases show that REM sleep behavior disorder and mental illness increase PD risk and that PD patients have lower cancer risk, but methodological concerns exist. Future epidemiologic studies of PD should be large, include detailed quantifications of exposure, and collect information on environmental exposures as well as genetic polymorphisms.
Collapse
Affiliation(s)
- Karin Wirdefeldt
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | | | |
Collapse
|
23
|
Louis ED, Benito-León J. Alzheimer's disease, Parkinson's disease and essential tremor: three common degenerative diseases with shared mechanisms? Eur J Neurol 2010; 17:765-6. [PMID: 20192981 DOI: 10.1111/j.1468-1331.2010.02976.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|