Multimodal Markers of Neurodegenerative Disorders at Presymptomatic Stages

1. Inclusion Criteria : 1. For all participants : * Male or female * Age ≥ 18 years * Signed Informed consent by the subject * Affiliated with a social security system or beneficiary of such a regime * Ability to undergo an MRI exam with Gadobutrol 2. For presymptomatic participants only : * Absence of a diagnosis of neurodegenerative disease. And at least one of the criteria : * Known carrier or relative of a patient carrying a mutation in a causal or at-risk responsible for a neurodegenerative disease * Isolated REM sleep behavioral disorder * Radiological isolated syndrome * Abnormal brain protein aggregates 3. For controls only : * Absence of symptoms or diagnosis of neurodegenerative disease (or criteria corresponding to at risk group) 2. Exclusion Criteria : * Clinical symptoms fulfilling the criteria of a neurodegenerative disease (see table in criteria section) * Refusal of blood draw or brain MRI * MRI contraindication (see criteria section) * Known allergy to gadoteric acid * Unwillingness to be informed in case of abnormal MRI (with a significant medical anomaly) * Pregnancy or breastfeeding. For women in fertile age a urine pregnancy test will be performed before the MRI. * Inability to understand information about the protocol * Person deprived of their liberty by judicial or administrative decision * Person under legal protection (legal guardianship, tutelage or maintenance of justice) * Person without any protection and unable to consent * Other medical, neurological, psychiatric, or social conditions that in the investigator's opinion are likely to interfere with study conduct.