You are here

Article Text

Article menu

Download PDFPDF

Movement disorders
Research paper
The Val158Met COMT polymorphism is a modifier of the age at onset in Parkinson's disease with a sexual dimorphism
  1. Stephan Klebe1,2,3,4,5,6,7,
  2. Jean-Louis Golmard8,
  3. Michael A Nalls9,
  4. Mohamad Saad10,11,
  5. Andrew B Singleton9,
  6. Jose M Bras12,
  7. John Hardy12,
  8. Javier Simon-Sanchez9,13,
  9. Peter Heutink13,
  10. Gregor Kuhlenbäumer14,
  11. Rim Charfi15,16,
  12. Christine Klein17,
  13. Johann Hagenah17,
  14. Thomas Gasser18,19,
  15. Isabel Wurster18,19,
  16. Suzanne Lesage1,2,3,
  17. Delia Lorenz20,
  18. Günther Deuschl20,
  19. Franck Durif21,
  20. Pierre Pollak22,
  21. Philippe Damier23,
  22. François Tison24,
  23. Alexandra Durr1,2,3,4,
  24. Philippe Amouyel25,26,27,
  25. Jean-Charles Lambert25,26,27,
  26. Christophe Tzourio28,29,
  27. Cécilia Maubaret30,
  28. Fanny Charbonnier-Beaupel1,2,3,
  29. Khadija Tahiri1,2,3,
  30. Marie Vidailhet2,3,6,31,
  31. Maria Martinez10,11,
  32. Alexis Brice1,2,3,4,6,
  33. Jean-Christophe Corvol1,2,3,5,15,
  34. French Parkinson's Disease Genetics Study Group and the International Parkinson's Disease Genomics Consortium (IPDGC)
  1. 1INSERM, UMR_S975, CR-ICM, Paris, France
  2. 2UPMC University Paris 06, UMR_S975, CR-ICM, Pitié-Salpêtrière Hospital, Paris, France
  3. 3CNRS UMR 7225, CR-ICM, Pitié-Salpêtrière Hospital, Paris, France
  4. 4Assitance Publique Hôpitaux de Paris, Département de Génétique et Cytogénétique, Hôpital de la Pitié-Salpêtrière, Paris, France
  5. 5INSERM, CIC-9503, Hôpital de la Pitié-Salpêtrière, Paris, France
  6. 6Assistance Publique Hôpitaux de Paris, Department of Neurology, Hôpital de la Pitié-Salpêtrière, Paris, France
  7. 7Department of Neurology, University Hospital Würzburg, Würzburg, Germany
  8. 8Assistance Publique Hôpitaux de Paris, Department of Biostatistics, Hôpital de la Pitié-Salpêtrière, Paris, France
  9. 9Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda Maryland, USA
  10. 10INSERM U1043, CPTP, Toulouse, France
  11. 11Paul Sabatier University, Toulouse, France
  12. 12Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
  13. 13Department of Clinical Genetics Section of Medical Genomics, VU Medical Center, Amsterdam, Netherlands
  14. 14Institute of Experimental Medicine, Christian-Albrechts University, Kiel, Germany
  15. 15Assistance Publique Hôpitaux de Paris, Department of Pharmacology, Hôpital de la Pitié-Salpêtrière, Paris, France
  16. 16Faculté de Médecine de Tunis, Université de Tunis El Manar, Centre National de Pharmacovigilance de Tunis, Service de Pharmacologie Clinique, Tunis, Tunisia
  17. 17Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
  18. 18Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
  19. 19Department of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
  20. 20Department of Neurology, UKS-H, Campus Kiel; Christian-Albrechts-University, Kiel, Germany
  21. 21Hôpital Gabriel Montpied, CHU de Grenoble, Department of Neurology, Clermont-Ferrand, France
  22. 22CHU de Grenoble, Department of Neurology, Grenoble, France
  23. 23CHU de Nantes, Centre d'Investigation Clinique, Nantes, France
  24. 24 Hôpital Haut-Lévêque, Department of Neurology, Pessac, France
  25. 25INSERM, U744, Lille, France
  26. 26Institut Pasteur de Lille, Lille, France
  27. 27Université Lille-Nord de France, Lille, France
  28. 28Université Pierre et Marie Curie—Paris 6, CNRS 7225 CRICM, ER4-UPMC Modélisation en recherche clinique, Hôpital Pitié-Salpêtrière, Paris, France
  29. 29INSERM UMR_S708, Neuroépidémiologie, Paris, France
  30. 30INSERM U897, Université Bordeaux Ségalen, Bordeaux, France
  31. 31“Movement Disorders and Basal Ganglia: Pathophysiology and experimental Therapeutics”, INSERM, UMR_S975, Paris, France
  1. Correspondence to Dr Jean-Christophe Corvol, Centre d'Investigation Clinique, Institut du Cerveau et de la Moelle épinière, Hôpital de la Pitié-Salpêtrière, 47 boulevard de l'Hôpital, Paris 75651 Cedex 13, France; jean-christophe.corvol{at}psl.aphp.fr.

Abstract

The catechol-O-methyltranferase (COMT) is one of the main enzymes that metabolise dopamine in the brain. The Val158Met polymorphism in the COMT gene (rs4680) causes a trimodal distribution of high (Val/Val), intermediate (Val/Met) and low (Met/Met) enzyme activity. We tested whether the Val158Met polymorphism is a modifier of the age at onset (AAO) in Parkinson's disease (PD). The rs4680 was genotyped in a total of 16 609 subjects from five independent cohorts of European and North American origin (5886 patients with PD and 10 723 healthy controls). The multivariate analysis for comparing PD and control groups was based on a stepwise logistic regression, with gender, age and cohort origin included in the initial model. The multivariate analysis of the AAO was a mixed linear model, with COMT genotype and gender considered as fixed effects and cohort and cohort-gender interaction as random effects. COMT genotype was coded as a quantitative variable, assuming a codominant genetic effect. The distribution of the COMT polymorphism was not significantly different in patients and controls (p=0.22). The Val allele had a significant effect on the AAO with a younger AAO in patients with the Val/Val (57.1±13.9, p=0.03) than the Val/Met (57.4±13.9) and the Met/Met genotypes (58.3±13.5). The difference was greater in men (1.9 years between Val/Val and Met/Met, p=0.007) than in women (0.2 years, p=0.81). Thus, the Val158Met COMT polymorphism is not associated with PD in the Caucasian population but acts as a modifier of the AAO in PD with a sexual dimorphism: the Val allele is associated with a younger AAO in men with idiopathic PD.

  • Movement Disorders
  • Neurogenetics
  • Parkinson's Disease

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/3.0/ and http://creativecommons.org/licenses/by-nc/3.0/legalcode

https://doi.org/10.1136/jnnp-2012-304475

Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    Introduction

    Parkinson's disease (PD) is a neurodegenerative disorder characterised by the loss of dopaminergic neurons in the mesencephalon. The diagnosis of PD is usually made when patients first notice symptoms of motor dysfunction (bradykinesia, tremor and rigidity) that are related to loss of the dopaminergic innervation in the striatum. However, the dopaminergic deficiency in the mesencephalon remains clinically silent until the concentration of dopamine has decreased by 60–80% in the striatum, and until 30–40% loss of dopaminergic neurons has been reached (1–7). Compensatory mechanisms may thus be involved to explain this delay in the occurrence of motor symptoms.

    In the central nervous system, two main enzymes, the monoamine oxidase B (MAOB) and the catechol-O-methyltranferase (COMT) metabolise dopamine. The human COMT gene (OMIM 116790) is localised on chromosome 22q11.2. The distribution of COMT activity in the population and in families indicates that it is regulated by a single autosomal locus with two codominant alleles.1 ,2 The substitution of valine (Val) by methionine (Met) at codon 158 (Val158Met) in the membrane-bound isoform, corresponding to codon 108 in the soluble form, results in a trimodal distribution of high, low and intermediate enzymatic activity. COMT activity is threefold to fourfold higher in the liver and red blood cells of 158Val patients than in those with the 158Met variant.3 ,4 There are ethnic differences in the distribution of the Val158Met genotype.5 About 25% of the Caucasian population is homozygous for the low activity variant (Met/Met), 25% is homozygous for the high activity variant (Val/Val) and 50% has the intermediate activity variant (Val/Met).6

    The influence of the COMT Val158Met polymorphism on non-motor symptoms in PD, particularly cognitive functions, has been studied7–11 but little is known about its effect on motor symptoms. In the present study, we hypothesise that COMT activity might modulate the age at onset (AAO) of motor symptoms in PD by modifying the bioavailability of the remaining endogenous dopamine in the striatum. Using the COMT Val158/108Met polymorphism as a surrogate marker of enzyme activity, we performed an association study in 16 609 patients and controls of European and North American origin.

    Patients and methods

    French samples

    Subjects with PD (n=1031) were recruited through the French network for the study of Parkinson's disease genetics associating 15 university hospitals across France. All patients were of European origin. Definite and probable PD was defined according to the UK Parkinson's Disease Society Brain Bank (UKPDSBB).12 The healthy controls (n=2061) of the French sample came from either the French Three-City (3C) cohort (n=1933)13 or the Parkinson's disease genetics network (n=128). The participants of the 3C cohort were non-institutionalised subjects over 65 years of age, randomly selected from the electoral rolls of three French cities. The control subjects were matched for gender with patients with PD.

    German samples

    The German samples consisted of three independent cohorts (Kiel, Lübeck and Tübingen). Patients with PD (n=648) and healthy controls (n=688) from the Kiel sample were from the Population Based Assessment of Genetic Risk Factors for PD study performed in northern Germany in cooperation with the Populationsgenetik (POPGEN) biobank.14 All participating patients with PD were diagnosed by board certified neurologists according to the UKPDSBB Criteria.12 Controls (n=688), also obtained by POPGEN, were matched to the cases by gender and geographical origin and were screened to confirm the absence of PD. The Lübeck sample consisted of 525 cases and 223 healthy controls collected in specialised outpatient clinics. All patients underwent a detailed neurological examination by a movement disorder specialist and the diagnosis of PD was established clinically according to the UKPDSBB.12 The controls underwent the same neurological examination as the patients. The PD cases (n=662) for the Tübingen cohort were collected by movement disorders specialists at the Universities of Munich and Tübingen, according to the UKPDSBB.12 Sample collection from controls (n=767) was performed as part of the Prospective validation of risk markers for the development of idiopathic Parkinson's disease (Idiopathic Parkinson Kohorte Syndroms, PRIPS) study in Tübingen.

    International Parkinson's Disease Genomics Consortium

    Genome-wide association studies-based data from three contributing cohorts from the International Parkinson's Disease Genomics Consortium was used in this study and have been described in detail elsewhere.15 ,16 This includes 937 cases of PD and 3033 controls from the US samples from the National Institute on Aging cohort, 744 cases and 2019 controls from the Dutch cohort, and 1648 cases and 2699 controls from the UK cohort.17–19

    All these studies were carried out in accordance with the Declaration of Helsinki and the rules for clinical good practice. All participants gave their informed consent. The local Ethical Committees approved the studies.

    AAO definition

    AAO was systematically determined at the time of inclusion by a retrospective interview. The AAO was defined as the first PD-related motor symptom (akinesia, tremor or rigidity) experienced by the patient for the French, Lübeck and Tübingen cohorts, and by the age at which PD was first diagnosed for the Kiel sample and the International Parkinson's Disease Genomics Consortium cohorts.

    Genotyping

    The COMT polymorphism G185A (rs4680) was analysed by an allelic discrimination Taqman assay (Applied Biosystems PRISM 7900 sequence detection system, Applied Biosystems, Foster City, USA) for the German samples or extracted from DNA array studies as described elsewhere.15 ,16 ,20–24

    Statistical analysis

    Descriptive statistics used numbers and percentages as qualitative variables and means and SDs as quantitative variables.

    Relationships between qualitative variables were tested using χ2 tests and comparisons between means of quantitative variables were performed using Student t tests for two groups and unbalanced analysis of variance (ANOVA) for more than two groups. The multivariate analysis for comparing PD and control groups was based on a stepwise logistic regression, with all variables included in the initial model and variables statistically significant with p<0.05 by the Wald test retained in the final model. The multivariate analysis of the AAO was first based on a mixed linear model, with the COMT genotype and gender considered as fixed effects and cohort and cohort-gender interaction considered as random effects. In a second step, two distinct models were fitted, one for men and one for women, with the COMT genotype as the fixed effect and the cohort as the random effect. In all mixed linear models, the COMT genotype was coded as a quantitative variable, namely as the number of ‘L’ alleles. Hardy-Weinberg equilibrium was tested using χ2 tests in each sample. All tests were two-sided, with a p value of 0.05 considered statistically significant. Computations were performed using the SAS V.9 statistical package.

    Results

    Characteristics of patients and controls

    A total of 17 665 subjects were available (6177 patients with PD and 11 488 controls). Due to insufficient DNA quantity or quality or missing clinical information 1056 specimens were excluded for further analysis. Finally, 16 609 subjects were genotyped for the rs4680 polymorphism and included in the analysis (5886 patients with PD and 10 723 healthy controls). The characteristics of subjects in the five cohorts are summarised in table 1. The mean AAO for patients with PD was 57.6±13.8 years. Cohorts of patients with PD were significantly different in terms of AAO (p<0.001) and sex ratio (p=0.04). The mean AAO was also significantly different between gender (male 57.1±13.7, female 58.3±13.9, p=0.001). Subsequent analyses thus included gender and cohorts in the multivariate model.

    View this table:
    Table 1

    Characteristics of subjects

    Distribution of the COMT polymorphism

    The distribution of the Val158Met polymorphism in the dataset is described in table 2. The distribution of the single nucleotide polymorphism (SNP) was in  Hardy-Weinberg equilibrium in patients (p=0.44) and controls groups (p=0.25). The distribution of genotypes (Val/Val, Val/Met and Met/Met) was similar and not significantly different in patients and controls (table 2, p=0.22). However, genotype distributions differed significantly among cohorts (p<0.001). The multivariate analysis including gender, cohorts and the age of PD and controls in the model found no significant association between the Val158Met polymorphism and PD (p=0.22). Altogether, these results failed to find an association between rs4680 and PD in a large population of Caucasian patients with PD and controls.

    View this table:
    Table 2

    Distribution of the COMT Val158Met polymorphism in PD and controls

    AAO and COMT polymorphism

    The AAO was analysed assuming a genetic codominant model for the Val158Met COMT polymorphism in accordance with its codominant effect on the enzyme activity. A significant difference of AAO was found for the French (47.9±13.3 for Val/Val compared with 50.2±13.1 for Met/Met, p=0.04) and the US samples (56.2±13.4 for Val/Val compared with 59.5±12.7 for Met/Met, p=0.03). For the UK, Dutch and German samples no significant changes could be found (data not shown).

    The univariate analysis for the whole PD sample (n=5886) found a significant difference of AAO according to genotype with an earlier AAO for those carrying the Val158 allele, corresponding to the high enzyme activity (table 3, p=0.04). The multivariate analysis confirmed the significant association of the AAO with the COMT polymorphism when cohorts and gender were included in the model (p=0.03). The difference of AAO was 1.2 years earlier for patients with the Val/Val genotype compared with patients with the Met/Met genotype (57.1±13.9 vs 58.3±13.5, p=0.017). Interestingly, this difference was higher in male patients (56.0±14.1 for Val/Val compared with 57.9±13.6 for Met/Met, p=0.007) than in female patients (58.6±13.4 for Val/Val compared with 58.8±13.3 for Met/Met, p=0.81) (table 3).

    View this table:
    Table 3

    Age at onset in patients with PD according to COMT Val158Met genotype

    Discussion

    This is the largest study in which the COMT polymorphism rs4680 (Val158Met) was genotyped in PD in 16 609 patients and controls from different European and North American samples. We show that the rs4680 polymorphism is a genetic modifier of the AAO in patients with idiopathic PD. Our results suggest a codominant effect of the COMT Val158Met polymorphism resulting in a modification of the AAO by 1.2 years between extreme genotypes (Val/Val and Met/Met). This effect was significant in men but not in women with a 1.9 years difference between extreme genotypes in men. This modifying effect was not associated with an increased risk of PD associated with the Val158Met polymorphism. This result confirms, in a larger cohort, the absence of association between this polymorphism and PD risk in the Caucasian population.7 ,25–27 In the French and US samples we revealed a significant earlier AAO associated with the Val/Val genotypes. In the remaining samples from Germany, the Netherlands and the UK no significant result has been shown. A possible explanation might be that these samples were underpowered.

    The effect of the COMT Val158Met polymorphism on AAO might be explained by a difference of metabolism of the endogenous dopamine in the striatum at disease onset. Indeed, patients carrying the Val158 allele (Val/Val and Val/Met) may have a reduced dopamine bioavailability because of a higher enzyme activity leading to earlier motor symptoms. Conversely, poor metabolisers (Met/Met) may have a greater dopamine bioavailability delaying their motor symptoms. The inverse U curve effect of dopamine concentration in the frontal cortex28 was elegantly validated in studies of working memory in healthy controls and schizophrenic patients demonstrating that the Val158Met COMT polymorphism has indeed functional consequences on brain function.29 ,30 In PD, studies on the impact of the Val158Met polymorphism on non-motor symptoms have produced conflicting results.7–11 No evidence was found for an association between the Val158Met genotype and daytime sleepiness or on neuropsychological measures of attention and executive function.9 ,10 Other studies showed that the genotype directly affects executive function in early stage PD; Val/Val patients have less frontoparietal activation on fMRI11 and better performance on executive tasks.8 ,11 A pharmacogenetic study showed that the COMT polymorphism determines the acute response to entacapone,31 although the motor response to levodopa alone was not modified by the COMT polymorphism.31 ,32 These results collectively show that the COMT polymorphism modifies the PD phenotype. Considering its frequency, it might have to be taken into account in the clinical management of patients with PD.

    An interesting result in our study was the gender difference of the COMT genotype effect on AAO. The AAO was not significantly different in women whereas it was 1.9 years earlier in men with the Val/Val genotype compared with the Met/Met genotype. A sexually dimorphic autosomal genetic association of the COMT gene has been well-recognised in psychiatric disorders but has not yet been described in PD. One of the best-replicated findings was the association of low enzymatic activity with obsessive-compulsive disorder in men, but not in women.33–35 In postmortem studies, the dorsolateral prefrontal cortex of women had lower COMT activity than men.36 Further evidence for gender differences comes from COMT knockout mice (COMT-/-).37 In this model dopamine levels in the frontal cortex are significantly increased in male COMT-/- mice compared with wild-type mice, but not in female COMT -/- mice. Sex hormones, especially oestrogen, probably contribute to explain gender differences. Oestrogens inhibit COMT mRNA expression in cells expressing oestrogen receptors.38 However the oestrogen hypothesis might only be a part of the explanation of the gender dimorphism in our study because (1) oestrogen levels fall in postmenopausal women, the age at which PD commonly occurs and (2) in mid-age men the COMT protein and activity levels rise considerably,39 despite steady oestradiol levels within this period.40 Bearing this in mind further pathophysiological mechanism could be responsible for the sexual dimorphism like additional gene implication or epigenetic regulation.41 A candidate gene involved in gender differences could be the monoamine oxidase B (MAOB; OMIM 309860), an X linked gene, which also participates in dopamine metabolism. The MAOB brain activity increases with age42 and its activity is regulated by epigenetic factors.43 Different SNPs of the MAOB44 and the combination of genotypes at risk for the MAOB and the COMT gene45 were suspected to be associated with PD. Interestingly, one MAOB SNP (rs1799836) was available in French patients with PD (n=992). In this subset, no significant association was found between AAO and this MAOB SNP either alone or in combination with the COMT rs4680 (data not shown).

    Our study may have some limitations although statistical biases were carefully avoided by performing multivariate analyses adjusting for cohort origin and gender. Because non-motor—and non-dopaminergic symptoms—may precede motor symptoms in PD, disease onset might not adequately reflect dopaminergic denervation in the striatum that might be modified by the COMT. Finally, other environmental modifiers, like tobacco, are also likely to contribute to the development of PD symptoms but environmental factors were not available in our dataset. Genetic forms of PD as well as genetic susceptibility factors such as mutations in the galactocerebrosidase gene were not systematically screened. Indeed, an association between heterozygous galactocerebrosidase gene mutation and the AAO has been suspected in PD.46 Future studies must integrate the effects of environmental and genetic factors, including the COMT polymorphism, that could affect the bioavailability of dopamine in general, and especially in individuals at risk for PD.

    In conclusion, our data indicate that the COMT polymorphism rs4680 (Val158Met) is a genetic modifier of AAO in patients with PD, with a higher effect in male patients than in female patients. This may be important for future diagnostic and therapeutic strategies.

    Acknowledgments

    We thank all study participants for their cooperation. The technical assistance of the DNA and cell bank of the Federative Institute for Neuroscience is gratefully acknowledged and the authors wish to thank Dr Merle Ruberg for critical review of the manuscript. We also thank the members of the French 3C Consortium: Annick Alpérovitch, Claudine Berr, Christophe Tzourio and Philippe Amouyel for allowing us to use part of the 3C cohort. This study was supported by grants from the German Federal Ministry of Education and Research (01GI0201), the Medical Faculty of the Kiel University, the Cluster of Excellence ‘‘Inflammation at Interfaces,’’ Christian-Albrechts University, Kiel, Ministry for Science, Commerce and Transportation of Schleswig-Holstein, Germany, and the German National Genome Research Network (NGFN) through the POPGEN biobank (BMBF 01GR0468). CK is a recipient of a career development award from the Hermann and Lilly Schilling Foundation. The US work was supported in part by the Intramural Research Programs of the National Institute on Aging project numbers Z01 AG000949-02. Portions of this study used the high-performance computational capabilities of the Biowulf Linux cluster at the National Institutes of Health, Bethesda, Md. (http://biowulf.nih.gov).

    References

    1. ↵
      1. Floderus Y,
      2. Wetterberg L
      . The inheritance of human erythrocyte catechol-O-methyltransferase activity. Clin Genet 1981;19:392–5.
      OpenUrlPubMedWeb of Science
    2. ↵
      1. Weinshilboum R,
      2. Raymond F
      . Variations in catechol-O-methyltransferase activity in inbred strains of rats. Neuropharmacology 1977;16:703–6.
      OpenUrlCrossRefPubMed
    3. ↵
      1. Lotta T,
      2. Vidgren J,
      3. Tilgmann C,
      4. et al
      . Kinetics of human soluble and membrane-bound catechol O-methyltransferase: a revised mechanism and description of the thermolabile variant of the enzyme. Biochemistry 1995;34:4202–10.
      OpenUrlCrossRefPubMedWeb of Science
    4. ↵
      1. Lachman HM,
      2. Papolos DF,
      3. Saito T,
      4. et al
      . Human catechol-O-methyltransferase pharmacogenetics: description of a functional polymorphism and its potential application to neuropsychiatric disorders. Pharmacogenetics 1996;6:243–50.
      OpenUrlCrossRefPubMedWeb of Science
    5. ↵
      1. McLeod HL,
      2. Syvanen AC,
      3. Githang'a J,
      4. et al
      . Ethnic differences in catechol O-methyltransferase pharmacogenetics: frequency of the codon 108/158 low activity allele is lower in Kenyan than Caucasian or South-west Asian individuals. Pharmacogenetics 1998;8:195–9.
      OpenUrlPubMed
    6. ↵
      1. Hernan MA,
      2. Checkoway H,
      3. O'Brien R,
      4. et al
      . MAOB intron 13 and COMT codon 158 polymorphisms, cigarette smoking, and the risk of PD. Neurology 2002;58:1381–7.
      OpenUrlAbstract/FREE Full Text
    7. ↵
      1. Eerola J,
      2. Launes J,
      3. Hellstrom O,
      4. et al
      . Apolipoprotein E (APOE), PARKIN and catechol-O-methyltransferase (COMT) genes and susceptibility to sporadic Parkinson's disease in Finland. Neurosci Lett 2002;330:296–8.
      OpenUrlCrossRefPubMed
    8. ↵
      1. Foltynie T,
      2. Goldberg TE,
      3. Lewis SG,
      4. et al
      . Planning ability in Parkinson's disease is influenced by the COMT val158met polymorphism. Mov Disord 2004;19:885–91.
      OpenUrlCrossRefPubMedWeb of Science
    9. ↵
      1. Hoogland J,
      2. de Bie RM,
      3. Williams-Gray CH,
      4. et al
      . Catechol-O-methyltransferase val158met and cognitive function in Parkinson's disease. Mov Disord 2010;25:25504.
      OpenUrlCrossRefPubMed
    10. ↵
      1. Rissling I,
      2. Frauscher B,
      3. Kronenberg F,
      4. et al
      . Daytime sleepiness and the COMT val158met polymorphism in patients with Parkinson disease. Sleep 2006;29:108–11.
      OpenUrlPubMed
    11. ↵
      1. Williams-Gray CH,
      2. Hampshire A,
      3. Robbins TW,
      4. et al
      . Catechol O-methyltransferase Val158Met genotype influences frontoparietal activity during planning in patients with Parkinson's disease. J Neurosci 2007;27:4832–8.
      OpenUrlAbstract/FREE Full Text
    12. ↵
      1. Hughes AJ,
      2. Daniel SE,
      3. Kilford L,
      4. et al
      . Accuracy of clinical diagnosis of idiopathic Parkinson's disease: a clinico-pathological study of 100 cases. J Neurol Neurosurg Psychiatry 1992;55:181–4.
      OpenUrlAbstract/FREE Full Text
    13. ↵
      3C Study Group. Vascular factors and risk of dementia: design of the Three-City Study and baseline characteristics of the study population. Neuroepidemiology 2003;22:316–25 .
      OpenUrlCrossRefPubMedWeb of Science
    14. ↵
      1. Krawczak M,
      2. Nikolaus S,
      3. von Eberstein H,
      4. et al
      . PopGen: population-based recruitment of patients and controls for the analysis of complex genotype-phenotype relationships. Community Genet 2006;9:55–61.
      OpenUrlCrossRefPubMedWeb of Science
    15. ↵
      1. Nalls MA,
      2. Plagnol V,
      3. Hernandez DG,
      4. et al
      . Imputation of sequence variants for identification of genetic risks for Parkinson's disease: a meta-analysis of genome-wide association studies. Lancet 2011;377:641–9.
      OpenUrlCrossRefPubMedWeb of Science
    16. ↵
      International Parkinson's Disease Genomics Consortium (IPDGC); Wellcome Trust Case Control Consortium 2 (WTCCC2). A two-stage meta-analysis identifies several new loci for Parkinson's disease. PLoS Genet 2011;7:e1002142.
      OpenUrlCrossRefPubMed
    17. ↵
      1. Simon-Sanchez J,
      2. Schulte C,
      3. Bras JM,
      4. et al
      . Genome-wide association study reveals genetic risk underlying Parkinson's disease. Nat Genet 2009;41:1308–12.
      OpenUrlCrossRefPubMedWeb of Science
    18. ↵
      1. Simon-Sanchez J,
      2. van Hilten JJ,
      3. van de Warrenburg B,
      4. et al
      . Genome-wide association study confirms extant PD risk loci among the Dutch. Eur J Hum Genet 2011;19:655–61.
      OpenUrlCrossRefPubMed
    19. ↵
      1. Spencer CC,
      2. Plagnol V,
      3. Strange A,
      4. et al
      . Dissection of the genetics of Parkinson's disease identifies an additional association 5’ of SNCA and multiple associated haplotypes at 17q21. Hum Mol Genet 2011;20:345–53.
      OpenUrlAbstract/FREE Full Text
    20. ↵
      1. Saad M,
      2. Lesage S,
      3. Saint-Pierre A,
      4. et al
      . Genome-wide association study confirms BST1 and suggests a locus on 12q24 as the risk loci for Parkinson's disease in the European population. Hum Mol Genet 2011;20:615–27.
      OpenUrlAbstract/FREE Full Text
    21. ↵
      1000 Genomes Project Consortium, Abecasis GR, Altshuler D, et al. A map of human genome variation from population-scale sequencing. Nature 2010;467:1061–73.
      OpenUrlCrossRefPubMedWeb of Science
    22. ↵
      1. Li Y,
      2. Willer CJ,
      3. Ding J,
      4. et al
      . MaCH: using sequence and genotype data to estimate haplotypes and unobserved genotypes. Genet Epidemiol 2010;34: 816–34.
      OpenUrlCrossRefPubMedWeb of Science
    23. ↵
      1. Price AL,
      2. Patterson NJ,
      3. Plenge RM,
      4. et al
      . Principal components analysis corrects for stratification in genome-wide association studies. Nat Genet 2006;38:904–9.
      OpenUrlCrossRefPubMedWeb of Science
    24. ↵
      1. Purcell S,
      2. Neale B,
      3. Todd-Brown K,
      4. et al
      . PLINK: a tool set for whole-genome association and population-based linkage analyses. Am J Hum Genet 2007;81:559–75.
      OpenUrlCrossRefPubMed
    25. ↵
      1. Goudreau JL,
      2. Maraganore DM,
      3. Farrer MJ,
      4. et al
      . Case-control study of dopamine transporter-1, monoamine oxidase-B, and catechol-O-methyl transferase polymorphisms in Parkinson's disease. Mov Disord 2002;17:1305–11.
      OpenUrlCrossRefPubMedWeb of Science
    26. ↵
      1. Hoda F,
      2. Nicholl D,
      3. Bennett P,
      4. et al
      . No association between Parkinson's disease and low-activity alleles of catechol O-methyltransferase. Biochem Biophys Res Commun 1996;228:780–4.
      OpenUrlCrossRefPubMedWeb of Science
    27. ↵
      1. Kalinderi K,
      2. Fidani L,
      3. Kourtesi G,
      4. et al
      . No association of the Val158Met COMT polymorphism with Parkinson's disease in the Greek population. Eur J Neurol 2008;15:e83.
      OpenUrlCrossRefPubMed
    28. ↵
      1. Goldman-Rakic PS,
      2. Muly EC III.,
      3. Williams GV
      . D(1) receptors in prefrontal cells and circuits. Brain Res Brain Res Rev 2000;31:295–301.
      OpenUrlCrossRefPubMedWeb of Science
    29. ↵
      1. Williams-Gray CH,
      2. Hampshire A,
      3. Barker RA,
      4. et al
      . Attentional control in Parkinson's disease is dependent on COMT val 158 met genotype. Brain 2008;131:397–408.
      OpenUrlAbstract/FREE Full Text
    30. ↵
      1. Tunbridge EM,
      2. Harrison PJ,
      3. Weinberger DR
      . Catechol-o-methyltransferase, cognition, and psychosis: Val158Met and beyond. Biol Psychiatry 2006;60:141–51.
      OpenUrlCrossRefPubMedWeb of Science
    31. ↵
      1. Corvol JC,
      2. Bonnet C,
      3. Charbonnier-Beaupel F,
      4. et al
      . The COMT Val158Met polymorphism affects the response to entacapone in Parkinson's disease: a randomized crossover clinical trial. Ann Neurol 2011;69:111–18.
      OpenUrlCrossRefPubMed
    32. ↵
      1. Contin M,
      2. Martinelli P,
      3. Mochi M,
      4. et al
      . Genetic polymorphism of catechol-O-methyltransferase and levodopa pharmacokinetic-pharmacodynamic pattern in patients with Parkinson's disease. Mov Disord 2005;20:734–9.
      OpenUrlCrossRefPubMedWeb of Science
    33. ↵
      1. Denys D,
      2. Van Nieuwerburgh F,
      3. Deforce D,
      4. et al
      . Association between the dopamine D2 receptor TaqI A2 allele and low activity COMT allele with obsessive-compulsive disorder in males. Eur Neuropsychopharmacol 2006;16:446–50.
      OpenUrlCrossRefPubMed
    34. ↵
      1. Poyurovsky M,
      2. Michaelovsky E,
      3. Frisch A,
      4. et al
      . COMT Val158Met polymorphism in schizophrenia with obsessive-compulsive disorder: a case-control study. Neurosci Lett 2005;389:21–4.
      OpenUrlCrossRefPubMedWeb of Science
    35. ↵
      1. Pooley EC,
      2. Fineberg N,
      3. Harrison PJ
      . The met(158) allele of catechol-O-methyltransferase (COMT) is associated with obsessive-compulsive disorder in men: case-control study and meta-analysis. Mol Psychiatry 2007;12:556–61.
      OpenUrlCrossRefPubMed
    36. ↵
      1. Chen J,
      2. Lipska BK,
      3. Halim N,
      4. et al
      . Functional analysis of genetic variation in catechol-O-methyltransferase (COMT): effects on mRNA, protein, and enzyme activity in postmortem human brain. Am J Hum Genet 2004;75:807–21.
      OpenUrlCrossRefPubMedWeb of Science
    37. ↵
      1. Gogos JA,
      2. Morgan M,
      3. Luine V,
      4. et al
      . Catechol-O-methyltransferase-deficient mice exhibit sexually dimorphic changes in catecholamine levels and behavior. Proc Natl Acad Sci USA 1998;95:9991–6.
      OpenUrlAbstract/FREE Full Text
    38. ↵
      1. Harrison PJ,
      2. Tunbridge EM
      . Catechol-O-methyltransferase (COMT): a gene contributing to sex differences in brain function, and to sexual dimorphism in the predisposition to psychiatric disorders. Neuropsychopharmacology 2008;33:3037–45.
      OpenUrlCrossRefPubMedWeb of Science
    39. ↵
      1. Tunbridge EM,
      2. Weickert CS,
      3. Kleinman JE,
      4. et al
      . Catechol-o-methyltransferase enzyme activity and protein expression in human prefrontal cortex across the postnatal lifespan. Cereb Cortex 2007;17:1206–12.
      OpenUrlAbstract/FREE Full Text
    40. ↵
      1. Bjornerem A,
      2. Straume B,
      3. Midtby M,
      4. et al
      . Endogenous sex hormones in relation to age, sex, lifestyle factors, and chronic diseases in a general population: the Tromso Study. J Clin Endocrinol Metab 2004;89:6039–47.
      OpenUrlCrossRefPubMedWeb of Science
    41. ↵
      1. Kaminsky Z,
      2. Wang SC,
      3. Petronis A
      . Complex disease, gender and epigenetics. Ann Med 2006;38:530–44.
      OpenUrlCrossRefPubMedWeb of Science
    42. ↵
      1. Volchegorskii IA,
      2. Shemyakov SE,
      3. Turygin VV,
      4. et al
      . Comparative analysis of age-related changes in activities of monoamine oxidase-B and antioxidant defense enzymes in various structures of human brain. Bull Exp Biol Med 2001;132:760–2.
      OpenUrlCrossRefPubMed
    43. ↵
      1. Launay JM,
      2. Del Pino M,
      3. Chironi G,
      4. et al
      . Smoking induces long-lasting effects through a monoamine-oxidase epigenetic regulation. PLoS One 2009;4:e7959.
      OpenUrlCrossRefPubMed
    44. ↵
      1. Gao X,
      2. Scott WK,
      3. Wang G,
      4. et al
      . Gene-gene interaction between FGF20 and MAOB in Parkinson disease. Ann Hum Genet 2008;72:157–62.
      OpenUrlCrossRefPubMedWeb of Science
    45. ↵
      1. Wu RM,
      2. Cheng CW,
      3. Chen KH,
      4. et al
      . The COMT L allele modifies the association between MAOB polymorphism and PD in Taiwanese. Neurology 2001;56:375–82.
      OpenUrlAbstract/FREE Full Text
    46. ↵
      1. Nichols WC,
      2. Pankratz N,
      3. Marek DK,
      4. et al
      . Mutations in GBA are associated with familial Parkinson disease susceptibility and age at onset. Neurology 2009;72:310–16.
      OpenUrlAbstract/FREE Full Text

    Footnotes

    • Collaborators The French Parkinson's Disease Genetics Study Group includes, Y Agid: AP-HP, Hôpital de la Pitié-Salpêtrière, Department of Neurology, 75013 Paris, France; M Anheim: AP-HP, Hôpital de la Pitié-Salpêtrière, Département de Génétique et Cytogénétique, Centre de Génétique Moléculaire et Chromosomique, 75013 Paris, France; A-M Bonnet: AP-HP, Hôpital de la Pitié-Salpêtrière, Department of Neurology, 75013 Paris, France; M Borg: Service de Neurologie, Hôpital Pasteur, Nice, France; A. Brice: AP-HP, Hôpital de la Pitié-Salpêtrière, Department of Neurology, 75013 Paris, France, AP-HP, Hôpital de la Pitié-Salpêtrière, Département de Génétique et Cytogénétique, Centre de Génétique Moléculaire et Chromosomique, 75013 Paris, France; E Broussolle: University of Lyon; Hospices Civils de Lyon, Neurological Hospital, Lyon, France; J-C Corvol: INSERM, Centre d'Investigation Clinique CIC-9503, Hôpital de la Pitié-Salpêtrière, Paris, France; Ph. Damier: CHU Nantes, CIC0004, Department of Neurology, Nantes, France; +A. Destée: University Lille-Nord de France, CHRU de Lille, Neurologie, Hôpital Roger Salengro, Lille Cedex, France; A Durr: AP-HP, Hôpital de la Pitié-Salpêtrière, Département de Génétique et Cytogénétique, Centre de Génétique Moléculaire et Chromosomique, 75013 Paris, France; F Durif: Hôpital Gabriel Montpied, Department of Neurology, Clermont-Ferrand, France; S Klebe: AP-HP, Hôpital de la Pitié-Salpêtrière, Département de Génétique et Cytogénétique, Centre de Génétique Moléculaire et Chromosomique, 75013 Paris, France; E Lohmann: AP-HP, Hôpital de la Pitié-Salpêtrière, Département de Génétique et Cytogénétique, Centre de Génétique Moléculaire et Chromosomique, 75013 Paris, France; M Martinez: INSERM U563, CPTP, Toulouse, France; C Penet: INSERM, U975, 75013 Paris, France; P Pollak: CHU de Grenoble, Department of Neurology, Grenoble, France; P Krack: CHU de Grenoble, Department of Neurology, Grenoble, France; O Rascol: Departments of Clinical Pharmacology and Neurosciences, Hospital and University Paul Sabatier of Toulouse, France; F Tison: Hôpital Haut-Lévêque, Department of Neurology, Pessac, France; C Tranchant: Department of Neurology, Hôpital Civil, Strasbourg, France; M Vérin: Service de Neurologie, Hôpital Pontchaillou, CHU de Rennes, Rennes, France; F Viallet: Service de Neurologie, CHU La Timone, Marseille, France and M Vidailhet: AP-HP, Hôpital de la Pitié-Salpêtrière, Department of Neurology, 75013 Paris, France. International Parkinson's Disease Genomics Consortium (IPDGC) includes—Michael A Nalls: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; Vincent Plagnol: UCL Genetics Institute, Gower Place, London, WC1E 6BT, UK; Jose M Bras: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Dena G Hernandez: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Manu Sharma: INSERM UMR 1043, CPTP, Toulouse, France; Una-Marie Sheerin: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Mohamad Saad: INSERM UMR 1043, CPTP, Toulouse, France, Paul Sabatier University, Toulouse, France; Javier Simón-Sánchez: Department of Clinical Genetics, Section of Medical Genomics, VU University Medical Centre, Amsterdam, The Netherlands; Claudia Schulte: Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, and DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany; Suzanne Lesage: INSERM, UMR_S975 (Formerly UMR_S679), Paris, France, Université Pierre et Marie Curie-Paris, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, UMR-S975, Paris, France, CNRS, UMR 7225, Paris, France; Sigurlaug Sveinbjörnsdóttir: Department of Neurology, Landspítali University Hospital, Reykjavík, Iceland, Department of Neurology, MEHT Broomfield Hospital, Chelmsford, Essex, UK, Queen Mary College, University of London, London, UK; Philippe Amouyel: 51INSERM U744, Lille, France, Institut Pasteur de Lille, Université de Lille Nord, Lille, France; Sampath Arepalli: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; Gavin Band: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Roger A Barker: Department of Neurology, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 2QQ; Céline Bellinguez: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Yoav Ben-Shlomo: Department of Social Medicine, Bristol University; Henk W Berendse: Department of Neurology and Alzheimer Center, VU University Medical Center, Amsterdam, The Netherlands; Daniela Berg: Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, and DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany; Kailash Bhatia: Department of Motor Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG; Rob MA de Bie: Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Alessandro Biffi: Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA, Program in Medical and Population Genetics, Broad Institute, 7 Cambridge Center, Cambridge, MA 02139, USA; Bas Bloem: Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Zoltan Bochdanovits: Department of Clinical Genetics, Section of Medical Genomics, VU University Medical Centre, Amsterdam, The Netherlands; Michael Bonin: Department of Medical Genetics, Institute of Human Genetics, University of Tübingen, Tübingen, Germany; Kathrin Brockmann: Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, and DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany; Janet Brooks: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; David J Burn: Newcastle University Clinical Ageing Research Unit, Campus for Ageing and Vitality Newcastle upon Tyne NE4 5PL UK; Gavin Charlesworth: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Honglei Chen: Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, North Carolina, USA; Patrick F Chinnery: Neurology M4104, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH UK; Sean Chong: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; Carl E Clarke: School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT, Department of Neurology, City Hospital, Sandwell and West Birmingham Hospitals NHS Trust, Dudley Road, Birmingham B18 7QH; Mark R Cookson: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; J Mark Cooper: Department of Clinical Neurosciences, UCL Institute of Neurology, Royal Free Campus, Rowland Hill Street, London NW3 2PF; Jean Christophe Corvol: INSERM, UMR_S975 (Formerly UMR_S679), Paris, France, Université Pierre et Marie Curie-Paris, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, UMR-S975, Paris, France, CNRS, UMR 7225, Paris, France, INSERM CIC-9503, Hôpital Pitié-Salpêtrière, Paris, France; Carl Counsell: University of Aberdeen, Division of Applied Health Sciences, Population Health Section, Polwarth building, Foresterhill, Aberdeen, AB25 2ZD; Philippe Damier: CHU Nantes, CIC0004, Service de Neurologie, Nantes, France; Jean-François Dartigues: INSERM U897, Université Victor Segalen, Bordeaux, France; Panos Deloukas: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK; Günther Deuschl37, 37Klinik für Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Christian-Albrechts-Universität Kiel, Kiel, Germany; David T Dexter: Parkinson's Disease Research Group, Faculty of Medicine, Imperial College London, 4th Floor, Burlington Danes Building, Hammersmith Hospital, Du Cane Road, W12 0NN London, UK; Karin D van Dijk: Department of Neurology and Alzheimer Center, VU University Medical Center, Amsterdam, The Netherlands; Allissa Dillman: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; Frank Durif: Service de Neurologie, Hôpital Gabriel Montpied, Clermont-Ferrand, France, Alexandra Dürr: INSERM, UMR_S975 (Formerly UMR_S679), Paris, France, Université Pierre et Marie Curie-Paris, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, UMR-S975, Paris, France, CNRS, UMR 7225, Paris, France, AP-HP, Pitié-Salpêtrière Hospital, Department of Genetics and Cytogenetics, Paris, France; Sarah Edkins: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK; Jonathan R Evans: Cambridge Centre for Brain Repair, Forvie Site, Robinson Way, Cambridge CB22PY, UK; Thomas Foltynie: Institute of Neurology, University College London, London, UK; Colin Freeman: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Jianjun Gao: Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, North Carolina, USA; Michelle Gardner: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Raphael Gibbs: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Alison Goate: Department of Psychiatry, Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA; Emma Gray: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK; Rita Guerreiro: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Ómar Gústafsson: deCODE genetics, Sturlugata 8, IS-101 Reykjavik, Iceland; Clare Harris: University of Aberdeen, Division of Applied Health Sciences, Population Health Section, Polwarth building, Foresterhill, Aberdeen, AB25 2ZD; Garrett Hellenthal: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Jacobus J van Hilten: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands; Albert Hofman: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Albert Hollenbeck: AARP, Washington DC, USA; Janice Holton: Queen Square Brain Bank for Neurological Disorders, Institute of Neurology, University College London, London, UK; Michele Hu: Department of Clinical Neurology, West Wing, Level 3, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU; Xuemei Huang : Departments of Neurology, Radiology, Neurosurgery, Pharmacology, Kinesiology & Bioengineering, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania; Heiko Huber: Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, and DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany; Gavin Hudson: Neurology M4104, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH UK; Sarah E Hunt: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK; Johanna Huttenlocher: deCODE genetics, Sturlugata 8, IS-101 Reykjavik, Iceland; Thomas Illig : Institute of Epidemiology, Helmholtz Zentrum München, German Research Centre for Environmental Health, Neuherberg, Germany; Pálmi V Jónsson: Department of Geriatrics, Landspítali University Hospital, Reykjavík, Iceland; Cordelia Langford: Cambridge Centre for Brain Repair, Forvie Site, Robinson Way, Cambridge CB22PY, UK; Andrew Lees: Queen Square Brain Bank for Neurological Disorders, Institute of Neurology, University College London, London, UK; Peter Lichtner: Institute of Human Genetics, Helmholtz Zentrum München, German Research Centre for Environmental Health, Neuherberg, Germany; Patricia Limousin: Institute of Neurology, Sobell Department, Unit of Functional Neurosurgery, Queen Square, London, UK; Grisel Lopez: Section on Molecular Neurogenetics, Medical Genetics Branch, NHGRI, National Institutes of Health, Bethesda, Maryland, USA; Delia Lorenz: Klinik für Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Christian-Albrechts-Universität Kiel, Kiel, Germany; Alisdair McNeill: Department of Clinical Neurosciences, UCL Institute of Neurology, Royal Free Campus, Rowland Hill Street, London NW3 2PF; Catriona Moorby: School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT; Matthew Moore, Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; Huw Morris: MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK; Karen E Morrison: School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT, Neurosciences Department, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 2TH; Ese Mudanohwo: Neurogenetics Unit, UCL Institute of Neurology/National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Sean S O'Sullivan: Queen Square Brain Bank for Neurological Disorders, Institute of Neurology, University College London, London, UK; Justin Pearson: MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK; Richard Pearson: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Joel S Perlmutter: Department of Psychiatry, Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA; Hjörvar Pétursson: deCODE genetics, Sturlugata 8, IS-101 Reykjavik, Iceland, Department of Medical Genetics, Institute of Human Genetics, University of Tübingen, Tübingen, Germany; Matti Pirinen: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Pierre Pollak: Service de Neurologie, CHU de Grenoble, Grenoble, France; Bart Post: Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Simon Potter: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK; Bernard Ravina: Translational Neurology, Biogen Idec, 14 Cambridge Center, Bio 6, Cambridge, Massachusetts, USA; Tamas Revesz: Queen Square Brain Bank for Neurological Disorders, Institute of Neurology, University College London, London, UK; Olaf Riess: Department of Medical Genetics, Institute of Human Genetics, University of Tübingen, Tübingen, Germany; Fernando Rivadeneira: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands; Patrizia Rizzu: Department of Clinical Genetics, Section of Medical Genomics, VU University Medical Centre, Amsterdam, The Netherlands; Mina Ryten: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Stephen Sawcer: University of Cambridge, Department of Clinical Neurosciences, Addenbrooke's hospital, Hills Road, Cambridge, CB2 0QQ, UK; Anthony Schapira: Department of Clinical Neurosciences, UCL Institute of Neurology, Royal Free Campus, Rowland Hill Street, London NW3 2PF; Hans Scheffer: Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Karen Shaw: Queen Square Brain Bank for Neurological Disorders, Institute of Neurology, University College London, London, UK; Ira Shoulson: Department of Neurology, University of Rochester, Rochester, New York 14620, USA; Ellen Sidransky: Section on Molecular Neurogenetics, Medical Genetics Branch, NHGRI, National Institutes of Health, Bethesda, Maryland, USA; Rohan de Silva: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Colin Smith: Department of Pathology, Wilkie Building, Teviot Place, Edinburgh, EH8 9AG; Chris CA Spencer: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Hreinn Stefánsson: deCODE genetics, Sturlugata 8, IS-101 Reykjavik, Iceland; Stacy Steinberg: deCODE genetics, Sturlugata 8, IS-101 Reykjavik, Iceland; Joanna D Stockton: School of Clinical and Experimental Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT; Amy Strange: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Zhan Su: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Kevin Talbot: University of Oxford, Department of Clinical Neurology, John Radcliffe Hospital, Oxford OX3 9DU; Carlie M Tanner: Clinical Research Department, The Parkinson's Institute and Clinical Center, Sunnyvale, California, USA; Avazeh Tashakkori-Ghanbaria: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK; François Tison: Service de Neurologie, Hôpital Haut-Lévêque, Pessac, France; Daniah Trabzuni: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Bryan J Traynor: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA; André G Uitterlinden: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands; Jana Vandrovcova: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Daan Velseboer: Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Marie Vidailhet: INSERM, UMR_S975 (Formerly UMR_S679), Paris, France, Université Pierre et Marie Curie-Paris, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, UMR-S975, Paris, France, CNRS, UMR 7225, Paris, France; Damjan Vukcevic: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; Robert Walker: Department of Pathology, Wilkie Building, Teviot Place, Edinburgh, EH8 9AG; Bart van de Warrenburg: Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Michael E Weale: King's College London, Department of Medical and Molecular Genetics, London SE1 9RT; Mirdhu Wickremaratchi: Department of Neurology, Cardiff University, Cardiff, UK; Nigel Williams: MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK; Caroline H Williams-Gray: Department of Neurology, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 2QQ; Sophie Winder-Rhodes: Department of Psychiatry and Medical Research Council/Wellcome Trust Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, UK; Kári Stefánsson, deCODE genetics, Sturlugata 8, IS-101 Reykjavik, Iceland; Maria Martinez: INSERM UMR 1043, CPTP, Toulouse, France, Paul Sabatier University, Toulouse, France; Peter Donnelly: Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7LJ, UK; John Hardy: Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Peter Heutink: Department of Clinical Genetics, Section of Medical Genomics, VU University Medical Centre, Amsterdam, The Netherlands; Alexis Brice: INSERM, UMR_S975 (Formerly UMR_S679), Paris, France, Université Pierre et Marie Curie-Paris, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, UMR-S975, Paris, France, CNRS, UMR 7225, Paris, France, AP-HP, Pitié-Salpêtrière Hospital, Department of Genetics and Cytogenetics, Paris, France; Thomas Gasser: Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, and DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany; Nicholas W Wood: UCL Genetics Institute, Gower Place, London, WC1E 6BT, UK, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG; Andrew B Singleton: Laboratory of Neurogenetics. National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.

    • Contributors SK drafting/revising the manuscript, study concept or design, analysis or interpretation of data, acquisition of data. JLG drafting/revising the manuscript, study concept or design, analysis or interpretation of data. MAN drafting/revising the manuscript, study concept or design, analysis or interpretation of data, acquisition of data. GK drafting/revising the manuscript and interpretation of data. RC revising the manuscript and analysis or interpretation of data. AB drafting/revising the manuscript, study concept or design, analysis or interpretation of data, acquisition of data. JCC drafting/revising the manuscript, study concept or design, analysis or interpretation of data, acquisition of data. GK, DL and GD were responsible for patient characterisation and sample collection of the Kiel sample. CK and JH were responsible for patient characterisation and sample collection of the Lübeck sample. TG and IW were responsible for patient characterisation and sample collection of the Tübingen sample. MAN, ABS, JMB, JHy, JSS, PH were responsible for patient characterisation and sample collection of the International Parkinson's Disease Genomics Consortium. SK, JCC, AB, SL, MS, MM, FD, PP, PD, FT, AD and MV were responsible for patient characterisation and sample collection of the French sample. PA, JCL, CT and CM were responsible for the 3C sample collection. FCB, KT assisted in experimental design and execution. All authors critically reviewed the manuscript.

    • Funding IPDGC: This US work was supported in part by the Intramural Research Programs of the National Institute on Aging, National Institute of Neurological Disorders and Stroke, National Institute of Environmental Health Sciences, National Human Genome Research Institute, National Institutes of Health, Department of Health and Human Services; project numbers Z01 AG000949-02 and Z01-ES101986. In addition this study was supported by the US Department of Defense, award number W81XWH-09-2-0128. Funding to support collection of a portion of the samples was obtained from the National Institutes of Health (grants NS057105 and RR024992), the American Parkinson Disease Association (APDA), Barnes Jewish Hospital Foundation and the Greater St Louis Chapter of the APDA. This work was supported in part by the Wellcome Trust/MRC Joint Call in Neurodegeneration award (WT089698) to the UK Parkinson's Disease Consortium (UKPDC) whose members are from the UCL/Institute of Neurology, the University of Sheffield and the MRC Protein Phosphorylation Unit at the University of Dundee. Additionally part of the study was undertaken at UCLH/UCL using funding through a Department of Health NIHR Biomedical Research Centre. This work was also supported by Parkinson's UK (Grants 8047 and J-0804) and the Medical Research Council (G0700943). Genotyping of UK replication cases on Immunochip was part of the Wellcome Trust Case Control Consortium 2 project which is funded by the Wellcome Trust (085475/B/08/Z and 085475/Z/08/Z). PD is partly supported by a Wolfson-Royal Society Merit award. The UK gene expression work was supported in part by the UK Medical Research Council (G0901254) to researchers based in the UCL Institute of Neurology and King's College London. JH receives support from the Reta Lila Weston Trust for Medical Research. This work was also supported by the Landspitali University Hospital Research Fund (S.Sv.), the Icelandic Research Council (S.Sv.), the European Community Framework Programme 7, People programme, IAPP on novel genetic and phenotypic markers of Parkinson's disease and Essential Tremor (Mark MD), contract no PIAP-GA-2008-230596 MarkMD. (H Petursson, J Holton). The KORA research platform (KORA: Cooperative Research in the Region of Augsburg; http://www.gsf.de/KORA) was initiated and financed by the ForschungszentrumfürUmwelt und Gesundheit (GSF), which is funded by the German Federal Ministry of Education, Science, Research and Technology and by the State of Bavaria. The study was additionally funded by the German National Genome Network (NGFNplus #01GS08134; German Ministry for Education and Research) and in addition by the German Federal Ministry of Education and Research (BMBF) NGFN (01GR0468) and in the frame of ERA-Net NEURON (01GW0908). This work was also supported by the Helmholtz Alliance Mental Health in an Ageing Society (HelMA, HA-215) funded by the Initiative and Networking Fund of the Helmholtz Association. The French GWA scan work was supported by the French National Agency of Research (http://www.agence-nationale-recherche.fr, ANR-08-MNP-012) and by the National Research Funding Agency (ANR-08-NEUR-004-01) in ERA-NET NEURON framework (http://www.neuron-eranet.eu). We also want to thank the Hersenstichting Nederland (http://www.hersenstichting.nl), the Neuroscience Campus Amsterdam and the section of Medical genomics, the Prinses Beatrix Fonds (http://www.prinsesbeatrixfonds.nl) for sponsoring this work. This study utilised the high-performance computational capabilities of the Biowulf Linux cluster at the National Institutes of Health, Bethesda, Md. (http://biowulf.nih.gov). DNA panels and samples from the NINDS Human Genetics Resource Center DNA and Cell Line Repository (http://ccr.coriell.org/ninds) were used in this study, as well as clinical data. The submitters that contributed samples are acknowledged in detailed descriptions of each panel (http://ccr.coriell.org/sections/Collections/NINDS/?SsId=10). The authors thank The French Parkinson's Disease Genetics Study Group: Y Agid, M Anheim, A-M Bonnet, M Borg, A Brice, E Broussolle, J-C Corvol, Ph Damier, A Destée, A Dürr, F Durif, S Klebe, E Lohmann, M Martinez, P Pollak, O Rascol, F Tison, C Tranchant, M Vérin, F Viallet and M Vidailhet. The authors thank the members of the French 3C consortium: Drs Annick Alpérovitch, Claudine Berr, Christophe Tzourio and Jean-Charles Lambert for giving us the possibility to use part of the 3C cohort; and Drs M Lathrop and D Zelenika for their support in generating the genome-wide molecular data. The UK brain samples for the gene expression studies were obtained from the MRC Sudden Death Brain Bank in Edinburgh. This study makes use of GWA data generated by the Wellcome Trust Case-Control consortium 2 (WTCCC2) on UK PD cases and on UK controls from the 1958 Birth Cohort (58BC) and National Blood Service (NBS). UK population control data was made available through WTCCC1. We thank Jeffrey Barrett for assistance with the design of the Immunochip.

    • Competing interests None.

    • Ethics approval Local ethics committees.

    • Disclosure Dr Klebe received funding from the Deutsche Forschungsgemeinschaft (DFG) (DFG Kl 1433/2-1). He received royalties from Thieme publishers. Dr Golmard reports no disclosures. Dr Nalls reports no disclosures. Dr Martinez reports no disclosures. Prof Singleton reports no disclosures. Dr Bras reports no disclosures. Prof. Hardy consults for Eisai Pharmaceuticals. Dr Javier Simon-Sanchez reports no disclosures. Dr Peter Heutink reports no disclosures. Prof Kuhlenbäumer received grants from the Deutsche Forschungsgemeinschaft (DFG), the regional government and the Christian-Albrechts-University Kiel. Prof Klein is supported by grants from the Hermann and Lilly Schilling Foundation and from the BMBF (01GI0201), and the Bachmann-Strauss Dystonia & Parkinson Foundation. She also received consulting fees from Centogene and honoraria for speaking from Shire and Merz Pharma. Dr Charfi reports no disclosures. Dr Johann Hagenah receives funding Bachmann-Strauss Dystonia Parkinson. Prof Gasser serves as an editorial board member of Parkinsonism and Related Disorders, Journal of Parkinson's Disease and Neurogenetics and is funded by Novartis Pharma, the Federal Ministry of Education and Research (BMBF) (NGFN-Plus and ERA-Net NEURON), the Helmholtz Association (HelMA, Helmholtz Alliance for Health in an Ageing Society) and the European Community (MeFoPa, Mendelian Forms of Parkinsonism). He received speakers’ honoraria from Novartis, Merck-Serono, Schwarz Pharma, Boehringer Ingelheim and Valeant Pharma and royalties for his consulting activities from Cefalon Pharma and Merck-Serono. Prof. Gasser holds a patent concerning the LRRK2 gene and neurodegenerative disorders. I Wurster reports funding by GlaxoSmithKline for travel to a Congress. no disclosures. Dr Lesage reports no disclosures. Dr Lorenz reports no disclosures. Prof Deuschl has received lecture fees from Orion, Lundbeck, Teva and Pfizer and has been serving as a consultant for TEVA. He received royalties from Thieme publishers. He is a government employee and he receives through his institution funding for his research from the German Research Council, the German Ministery of Education and Health and Medtronic. Dr Saad reports no disclosures. Prof Durif reports no disclosures. Prof Pollak received speaker honoraria for from Novartis and Medtronic. Prof Damier served on the European advisory board for Lundbeck-Teva and received honoraria for conferences given on behalf Novartis and Glaxo SmithKline. Prof Tison has received speaker honoraria from UCB, Novartis, Lundbeck, GSK, Boehringer Ingelheim and Aguettant; served on scientific advisory board for Novartis, Addex pharmaceuticals; received research grant from Novartis and received funding for travel from Novartis, UCB, Lunbeck. Dr Durr received honoraria from Pfizer Inc. for participating to the Global TTR FAP Genetics Advisory Board, and received research support for the French Agency for Research. Dr Maubaret is funded by the foundation ‘Pour la recherché médicale’ (FRM, France) and reports no disclosures. Dr Amouyel received honoraria from serving on the medical advisory board of Total and Ipsen, for lectures for Sanofi, Pfizer, Servier and holds stocks from Genoscreen. Dr Lambert reports no disclosures. Dr Tzourio reports no disclosures. Dr Charbonnier-Beaupel reports no disclosures. Ms Tahiri reports no disclosures. Prof Vidailhet had institutional (ANR, DHOS-INSERM) and Patient's association (France Parkinson) research grants. Prof Brice received honoraria from the Wolfson Foundation for reviewing scientific project, and received research support from the French Agency for Research, Programme Hospitalier de Recherche Clinique, European Community and patients associations. Dr Jean-Christophe Corvol received research grants from INSERM and APHP, and received speaker's honoraria and travel reimbursements from Lundbeck, Biogen and Schering-Plough.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Open Access This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/3.0/