Multimodal Biocollection Linked to the French Register of Intracranial Aneurysms

Inclusion criteria for sporadic ICA cases: * Any adult patient consulting for a definite and typical bifurcation AIC authenticated on MRI and/or cerebral arteriography * Aneurysm discovered less than a year ago, with initial imaging (MRI and/or CTA and DSA) available * Written consent obtained for study participation * Patient covered by a social security plan Inclusion criteria for index and related cases (familial forms) of intracranial aneurysms (ICA): * Index case: Any adult patient consulting for a definite and typical bifurcation ICA presenting at least one other case with ICA related (child, parent, brother, sister) detected by MRI with at least one Time of Flight (TOF) sequence. * Family relatives: children, parents, brothers, sisters, of legal age, of patients with a family history of definite, typical bifurcation AIC (≥ 4 affected), Screening to be performed using MRI with at least a Time of Flight (TOF) sequence. * Written consent to participate in the study * Patient and relatives covered by a social security plan Exclusion Criteria: * Syndromic diagnosis known to cause ICA: Marfan syndrome, OSA with SMAD 3, Elhers Danlos syndrome type II and IV, Autosomal Dominant Cystic Fibrosis, Moya-Moya syndrome * AIC with : Dissecting or fusiform, Associated with arteriovenous malformation, Blister-like, Mycotic * Cerebral white matter pathology detected on MRI evoking : Col4a1 mutation * Patient under guardianship or conservatorship * Person under court protection * Contraindication to an MRI scan