The aim of this study is to determine whether a significant reduction in the total level of alpha-synuclein and significant increase in the oligomeric form of alpha-synuclein and therefore the ratio oligomeric:total alpha-synuclein occurs in patients with Parkinson disease compared to patients with drug-induced parkinsonian syndrome.

Inclusion Criteria

• The patient must have given their free and informed consent and signed the consent form

• The patient must be insured or the beneficiary of an insurance policy

• The patient is less than 55 years old

• For patients with acquired parkinsonian syndrome (UKPDSBB criteria) currently at HOEHN and YAHR stage ≤3:

  • For patients recruited via a psychiatrist: after anti-dopamine treatment
  • For patients recruited via a neurologist: having a recent diagnosis (≤2 years) of Parkinson disease

Exclusion Criteria:

• The subject is participating in another study
• The subject is in an exclusion period determined by a previous study
• The patients is under judicial protection
• The subject or their representative refused to sign the consent form
• It proves impossible to give the subject or their representative clear information.
• Patients with atypical degenerative parkinsonian syndrome
• Patients with vascular, post-traumatic, metabolic, toxic or genetic parkinsonian syndrome
• Appearance of parkinsonian syndrome prior to treatment with anti-dopamine
• Injection of botulinum toxin into the salivary glands
• Contra-indication on DAT-scan (unbalanced dysthyroidism, allergy, treatment with bupropion or amphetaminergics)
• Poor oral health (polyposis, gingivostomatitis) observed during the odontologist visit
• Patients not taking anti-psychotics with parkinsonian syndrome and normal DAT-scan

Subjects will be recruited from three centres:

Patients hospitalized in the Quissac psychiatric unit Patients followed in the CHU Nimes neurological department for idiopathic Parkinson Patients followed in the CHU Montpellier neurological department