Amyotrophic Lateral Sclerosis (ALS) is the most common motor neuron disease in adults. This longitudinal study involves three cohorts of participants: patients with sporadic or hereditary ALS, asymptomatic individuals carrying pathogenic mutations responsible for ALS, and control subjects. In this study, a skin biopsy and blood sampling will be performed at the initial visit (M0), then at M12 (+/- 2 months) for patients, and at M36 (+/- 12 months) for asymptomatic carriers of pathogenic mutations. The aim of this research is to model ALS pathology using fibroblasts derived from the patients' skin biopsies.

Amyotrophic Lateral Sclerosis (ALS) is the most common motor neuron disease in adults. This longitudinal study involves three cohorts of participants: patients with sporadic or hereditary ALS, asymptomatic individuals carrying pathogenic mutations responsible for ALS, and control subjects. In this study, a skin biopsy and blood sampling will be performed at the initial visit (M0), then at M12 (+/- 2 months) for patients, and at M36 (+/- 12 months) for asymptomatic carriers of pathogenic mutations. The aim of this research is to model ALS pathology using fibroblasts derived from the patients' skin biopsies.

Inclusion criteria common to all 3 populations:

• adults, both sexes
• with written consent to participate in the study
• affiliated to a social security scheme

ALS patients :

• patients with ALS according to the revised El Escorial criteria :
• with a hereditary form of ALS, defined by the presence of a family history of ALS or by the demonstration of a pathogenic mutation in the patient or
• with a juvenile form of the disease, defined by onset of symptoms at less than 30 years of age or
• with a sporadic form of ALS

Asymptomatic mutation carriers :

- Asymptomatic individuals who carry a mutation causing ALS but have not developed symptoms.

Healthy subjects:

• control individuals, taking into account male/female and close age matching

Exclusion Criteria:

• with a known skin disease (acne, atopic dermatitis, psoriasis, melanoma, skin carcinoma, rosacea, scabies; as referenced on http://dermato-info.fr/), which in the investigator's opinion constitutes a contraindication to skin biopsy
• have a platelet count of less than 75,000/mm3 in a laboratory test less than 3 months old,
• with a proven allergy to lidocaine or prilocaine,
• Pregnant or breast-feeding women, or subjects under guardianship, curatorship or safeguard of justice.
• Patient's condition which, in the opinion of the investigator, is incompatible with skin sampling or participation in the study.
• Participation in a clinical trial (involving a drug) or other interventional research if this interferes with FIBRALS research.