Establishment of a CSF Bank for the Development of Biomarkers of Smooth Muscle Cell (SMC) Damage in Monogenic Cerebral Small Vessel Disease

For patients woth monogenic cSVD : Inclusion Criteria: * Patients aged between 18 and 80 years at the time of inclusion * Diagnosis confirmed by detection of a pathogenic mutation in the NOTCH3 gene characteristic of CADASIL, or in another gene responsible for other forms of monogenic cSVD (such as COL4A1, COL4A2, HTRA1). * Beneficiary of a social security system * Having given their written consent Non inclusion Criteria: * Contraindication to lumbar puncture: * Haemostasis disorder (severe thrombocytopenia \<60,000/mm3, PT abnormalities, INR\>1.5 and/or aPTT\>1.5) or anticoagulant use. * Spinal plaque in or near the lumbar region (surgery) that may interfere with CSF collection * Behavioural disorder that may interfere with the sampling process * Intracranial process, intracranial hypertension or risk of involvement on imaging * Skin lesions (inflammation or infection of any kind) or developmental abnormality (myelomeningocele) adjacent to the puncture site * Person referred to in articles L. 1121-5 to L. 1121-8 and L. 1122-12 of the public health code, defined as : * Pregnant, parturient or breastfeeding woman * Person deprived of liberty by judicial or administrative decision * Person hospitalised without consent and not subject to a legal protection measure, and person admitted to a health or social establishment for purposes other than research * Minor * Person of full age subject to a legal protection measure (guardianship, curators or safeguard of justice), person of full age unable to express their consent and not subject to a protection measure * Person subject to an exclusion period for another research * Patients participating in other interventional research * Contraindication to lumbar puncture: * Haemostasis disorder (severe thrombocytopenia \<60,000/mm3, PT abnormalities, INR\>1.5 and/or aPTT\>1.5) or anticoagulant use. * Spinal plaque in or near the lumbar region (surgery) that may interfere with CSF collection * Spinal plaque (surgery) * Behavioural disorder that may interfere with the sampling process * Intracranial process, intracranial hypertension or risk of involvement on imaging * Skin lesions (psoriasis, infection....)inflammation or infection of any kind) or developmental abnormality (myelomeningocele) adjacent to the puncture site * Person referred to in articles L. 1121-5 to L. 1121-8 and L. 1122-12 of the public health code, defined as * Pregnant, parturient or breastfeeding woman * Person deprived of liberty by judicial or administrative decision * Person hospitalised without consent and not subject to a legal protection measure, and person admitted to a health or social establishment for purposes other than research * Minor * Person of full age subject to a legal protection measure (guardianship, curators or safeguard of justice), person of full age unable to express their consent and not subject to a protection measure * Person subject to an exclusion period for another research * Patients participating in other interventional research For control patients ( selection after CSF sampling): Inclusion criteria : * Subject aged 18-80 years at the time of inclusion * Imaging done: strictly normal CT scan OR MRI showing no abnormality suggestive of cSVD * Beneficiary of a social security system * Having had CSF and blood samples taken as part of the treatment * Agreement to use blood and CSF samples remainders for research purposes (information and non-opposition). * Women who were pregnant at the time the samples were taken will not be offered to participate in the study Non inclusion criteria : * Any previously identified intracranial vascular pathology requiring specific management (vasculitis, acute reversible angiopathy, severe intracranial atheroma) * Acute or chronic infectious disease (meningitis or meningoencephalitis) * Known pregnancy * Persons participating in other interventional research * Preparation and freezing time for blood and CSF samples is more than 4 hours