Neurofilament Assay for the Diagnosis of ALS

Inclusion criteria : Subjects with first and/or second motor neuron disease, evolving clinically and/or electrically over at least 12 months, not meeting the diagnostic criteria for ALS (revised El Escorial criteria): * Isolated peripheral motor neuron disease (at least one region of the PNM) OR * Isolated central motor neuron involvement (at least two areas of the MNC) OR * associated involvement of the MNP and MNC but in the presence of an associated pathology responsible for a persistent diagnostic doubt (double narrow cervical and lumbar canal, associated evolving cancer evoking a paraneoplastic syndrome without specific antibody found) Age superior to 18 years Management and follow-up in one of the French ALS centers Patient able to express his non-opposition Affiliation with social security or beneficiary of such a plan Non-inclusion criteria: Refusal of the patient Person under a legal protection measure (guardianship, curatorship or safeguard of justice). Person deprived of liberty by judicial or administrative decision.