title: Evolution of prodromal clinical markers of Parkinson disease in a GBA mutation-positive cohort.
abstract: OBJECTIVE
  Numerically, the most important genetic risk factor for the development of Parkinson disease (PD) is the presence of a glucocerebrosidase gene (GBA) mutation.
  
  
  OBJECTIVE
  To evaluate longitudinally and clinically a GBA mutation-positive cohort and the evolution of the prodromal features of PD.
  
  
  METHODS
  Participants in a study of the etiology and prodrome of PD were reevaluated in this clinic-based 2-year follow-up report. Patients with type 1 Gaucher disease (GD) and heterozygous GBA mutation carriers were recruited in 2010 from the Lysosomal Storage Disorder Unit at the Royal Free Hospital, London, England. Thirty patients who previously received a diagnosis of type 1 GD, 28 heterozygous GBA mutation carriers, and 26 genetically unrelated controls were included. Exclusion criteria included a diagnosis of PD or dementia for both the patients with GD and the GBA mutation carriers and any existing neurological disease for the controls.
  
  
  METHODS
  Assessment was performed for clinical markers using standardized scales for hyposmia, rapid eye movement sleep behavior disorder, depression, autonomic dysfunction, cognitive function, and parkinsonian motor signs (using the Unified Parkinson's Disease Rating Scale motor subscale [UPDRS part III]).
  
  
  RESULTS
  Over 2 years, depression scores were significantly worse for heterozygous carriers (mean baseline, 0.65; mean follow-up, 2.88; P = .01), rapid eye movement sleep behavior disorder scores were significantly worse for patients with GD (mean baseline, 0.93; mean follow-up, 2.93; P < .001) and heterozygotes (mean baseline, 0.10; mean follow-up, 2.30; P < .001), and UPDRS part III scores were significantly worse for patients with GD (mean baseline, 4.29; mean follow-up, 7.82; P < .001) and heterozygotes (mean baseline, 1.97; mean follow-up, 4.50; P < .001). For controls, there was a small but significant deterioration in the UPDRS part II (activities of daily living) score (mean baseline, 0.00; mean follow-up, 0.58; P = .006). At 2 years, olfactory and cognitive assessment scores were lower in patients with GD and heterozygotes compared with controls, but they did not differ significantly from baseline. When the results from the patients with GD and the heterozygotes were combined, a significant deterioration from baseline was observed, as reflected in the Rapid Eye Movement Sleep Behaviour Disorder Questionnaire (mean baseline, 0.51; mean follow-up, 2.63; P < .001), Beck Depression Inventory (mean baseline, 1.72; mean follow-up, 4.44; P = .002), and UPDRS part II (mean baseline, 0.88; mean follow-up, 2.01; P < .001) and part III scores (mean baseline, 3.09; mean follow-up, 6.10; P < .001) (all P < .01), and at 2 years, significant differences in University of Pennsylvania Smell Identification Test, Unified Multiple System Atrophy Rating Scale, Mini-Mental State Examination, Montreal Cognitive Assessment, and UPDRS part II and part III scores were observed between patients with GD/heterozygotes and controls (all P < .05).
  
  
  CONCLUSIONS
  This study indicates that, as a group, GBA mutation-positive individuals show a deterioration in clinical markers consistent with the prodrome of PD. Within this group of individual, 10% appear to be evolving at a more rapid rate.
authors.affiliation: Department of Clinical Neurosciences, Institute of Neurology, University College London, London, England.
authors.forename: Michelle
authors.initials: M
authors.lastname: Beavan
authors.affiliation: Department of Clinical Neurosciences, Institute of Neurology, University College London, London, England.
authors.forename: Alisdair
authors.initials: A
authors.lastname: McNeill
authors.affiliation: Department of Clinical Neurosciences, Institute of Neurology, University College London, London, England.
authors.forename: Christos
authors.initials: C
authors.lastname: Proukakis
authors.affiliation: Lysosomal Storage Disorders Unit, Royal Free Hospital, Royal Free London NHS Foundation Trust, and Department of Haematology, University College London, London, England.
authors.forename: Derralynn A
authors.initials: DA
authors.lastname: Hughes
authors.affiliation: Lysosomal Storage Disorders Unit, Royal Free Hospital, Royal Free London NHS Foundation Trust, and Department of Haematology, University College London, London, England.
authors.forename: Atul
authors.initials: A
authors.lastname: Mehta
authors.affiliation: Department of Clinical Neurosciences, Institute of Neurology, University College London, London, England.
authors.forename: Anthony H V
authors.initials: AH
authors.lastname: Schapira
mesh_terms: D000368:Aged; D015415:Biomarkers; D018450:Disease Progression; D005260:Female; D005776:Gaucher Disease / Q000235:genetics* / Q000503:physiopathology; D005962:Glucosylceramidase / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D010300:Parkinson Disease / Q000235:genetics* / Q000503:physiopathology; D062706:Prodromal Symptoms; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D005962:Glucosylceramidase