title: Age at onset and Parkinson disease phenotype.
abstract: OBJECTIVE
  To explore clinical phenotype and characteristics of Parkinson disease (PD) at different ages at onset in recently diagnosed patients with untreated PD.
  
  
  METHODS
  We have analyzed baseline data from the Parkinson's Progression Markers Initiative database. Four hundred twenty-two patients with a diagnosis of PD confirmed by DaTSCAN imaging were divided into 4 groups according to age at onset (onset younger than 50 years, 50-59 years, 60-69 years, and 70 years or older) and investigated for differences in side, type and localization of symptoms, occurrence/severity of motor and nonmotor features, nigrostriatal function, and CSF biomarkers.
  
  
  RESULTS
  Older age at onset was associated with a more severe motor and nonmotor phenotype, a greater dopaminergic dysfunction on DaTSCAN, and reduction of CSF α-synuclein and total tau. The most common presentation was the combination of 2 or 3 motor symptoms (bradykinesia, resting tremor, and rigidity) with rigidity being more common in the young-onset group. In about 80% of the patients with localized onset, the arm was the most affected part of the body, with no difference across subgroups.
  
  
  CONCLUSIONS
  Although the presentation of PD symptoms is similar across age subgroups, the severity of motor and nonmotor features, the impairment of striatal binding, and the levels of CSF biomarkers increase with age at onset. The variability of imaging and nonimaging biomarkers in patients with PD at different ages could hamper the results of future clinical trials.
authors: From the Department of Medicine (G.P., D.J.B., N.P.), Neurology Imaging Unit, Imperial College London, Hammersmith Hospital, London, UK; Department of Translational Medical Sciences (G.P., N.F.), Federico II University of Naples; Salvatore Maugeri Foundation (N.F.), IRCCS, Scientific Institute of Telese, Telese Terme (BN), Italy; and Department of Clinical Medicine-Center for Functionally Integrative Neuroscience (D.J.B., N.P.), Aarhus University, Denmark.
authors: Gennaro
authors: G
authors: Pagano
authors: From the Department of Medicine (G.P., D.J.B., N.P.), Neurology Imaging Unit, Imperial College London, Hammersmith Hospital, London, UK; Department of Translational Medical Sciences (G.P., N.F.), Federico II University of Naples; Salvatore Maugeri Foundation (N.F.), IRCCS, Scientific Institute of Telese, Telese Terme (BN), Italy; and Department of Clinical Medicine-Center for Functionally Integrative Neuroscience (D.J.B., N.P.), Aarhus University, Denmark.
authors: Nicola
authors: N
authors: Ferrara
authors: From the Department of Medicine (G.P., D.J.B., N.P.), Neurology Imaging Unit, Imperial College London, Hammersmith Hospital, London, UK; Department of Translational Medical Sciences (G.P., N.F.), Federico II University of Naples; Salvatore Maugeri Foundation (N.F.), IRCCS, Scientific Institute of Telese, Telese Terme (BN), Italy; and Department of Clinical Medicine-Center for Functionally Integrative Neuroscience (D.J.B., N.P.), Aarhus University, Denmark.
authors: David J
authors: DJ
authors: Brooks
authors: From the Department of Medicine (G.P., D.J.B., N.P.), Neurology Imaging Unit, Imperial College London, Hammersmith Hospital, London, UK; Department of Translational Medical Sciences (G.P., N.F.), Federico II University of Naples; Salvatore Maugeri Foundation (N.F.), IRCCS, Scientific Institute of Telese, Telese Terme (BN), Italy; and Department of Clinical Medicine-Center for Functionally Integrative Neuroscience (D.J.B., N.P.), Aarhus University, Denmark. nicola.pavese@imperial.ac.uk.
authors: Nicola
authors: N
authors: Pavese
mesh_terms: D017668:Age of Onset; D000368:Aged; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D015415:Biomarkers / Q000097:blood / Q000134:cerebrospinal fluid; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000503:physiopathology; D016208:Databases, Factual; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000503:physiopathology*; D010446:Peptide Fragments / Q000134:cerebrospinal fluid; D010641:Phenotype; D010766:Phosphorylation; D011699:Putamen / Q000000981:diagnostic imaging / Q000503:physiopathology; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon; D014527:Uric Acid / Q000097:blood; D051844:alpha-Synuclein / Q000134:cerebrospinal fluid; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; C054369:MAPT protein, human; D010446:Peptide Fragments; C497604:SNCA protein, human; D051844:alpha-Synuclein; C075222:amyloid beta-protein (1-42); D016875:tau Proteins; D014527:Uric Acid