This study is being done in order to create a registry (list) of people interested in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) research. It may be that you have a family member or other loved one with CADASIL, or that you may have CADASIL or are at risk. Participation means that your name will be added to a list of people who will be invited to participate in future research studies on CADASIL. Participants must be 18 years or older, and will remain on the registry until they request to be removed.

The purpose of this registry is to allow Dr. Jane Paulsen and her CADASIL research teams to contact individuals on the list who may fit a study's eligibility requirements. All individuals interested in CADASIL research who either have a family member or loved one, or are at risk themselves, are eligible to participate in this registry. Information collected as part of the registry will be used solely to determine potential participant's eligibility to participate research.

A patient registry is an organized system that uses observational study methods to collect uniform data (clinical and other) to evaluate specified outcomes for a population defined by a particular disease, condition, or exposure, and that serves a predetermined scientific, clinical, or policy purpose(s).

Inclusion Criteria:

• 18 years of age or older
• have a loved one or a family member with CADASIL, or are at-risk for CADASIL themselves

Exclusion Criteria:

• Under 18 years of age

Study team will inform the lay community and professional society's memberships of the registry to assist with referrals for enrollment. Participants who are being contacted for other CADASIL research projects will be asked whether they would also like to enroll in the registry. Clinicians or other members of a patient's care team may also recruit participants out of their clinics.