Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy (CADASIL) Study

A composite Cognitive Executive Function Score will be reported based on data from two electronic assessments (Favorites and Match). Favorites tests both episodic and associative memory and consists of 2 learning trials followed by an immediate recall trial, 10 minute delayed recall, and delayed recognition trials. The Match assessment tests the processing speed and executive functions. The primary performance metric is the total correct score in 2 minutes. Scores are reported on a continuous scale with greater values indicating better performance. Demographically adjusted regression based z score for Favorites Total Recall and Match Total Correct are calculated to produce the composite score.

MRI structural integrity is measured using available analytic packages as well as newly validated outcome measures from the investigator's imaging core. MRI outcomes will reflect changes in the total brain volume from two time points. Less volumes will reflect greater brain loss and greater change over time will suggest a more rapid rate of progression.

MRI structural integrity is measured using available analytic packages as well as newly validated outcome measures from the investigator's imaging core. MRI outcomes will reflect changes in the total cerebral spinal fluid volume from two time points. Less volumes will reflect greater brain loss and greater change over time will suggest a more rapid rate of progression.

MRI functional integrity is measured using available analytic packages as well as newly validated outcome measures from the investigator's imaging core. MRI outcomes will reflect the strength of connectivity among different areas of the brain. Levels of connectivity will be associated with cognitive performances. Greater connectivity is associated with better cognition.

Blood will be analyzed using validated assays to measure the amount of NfL. Greater levels of NfL reflect worsened brain atrophy and change over time will demonstrate worsening over time.

Functional capacity is assessed using the WHODAS instrument. The measure consists of 12 items and allows responses on a 5-point scale for each item, the total possible range of scores is converted to 0-100 where 0 is no disability and 100 is full disability. The change in total WHODAS score from baseline to 36 months will show the rate of progression in loss of capacity.

CADASIL severity is determined using established disease-specific scales involving the frequency, severity, and duration of clinical signs and symptoms of CADASIL. The CADASIL scale is a 12-item scale of CADASIL symptoms and signs. Each item is given a weighted score according to a large sample of patients in Europe. A summary of all items is the total CADASIL score which can range from 0-25. Higher scores represent greater CADASIL severity. Change in total score from baseline to 36 months is used to measure the rate of symptomatic worsening or improvements over time.

Date of disease onset is determined by family and medical history and self-, proxy- and clinician-reported symptoms and signs. Earlier disease onset will suggest worsened burden for the participant.

There are various methods used to define the NOTCH3 variations: Specific mutations are documented in available databases and hypothesis testing will include those with and without a cysteine residue and the location of variant as determined by the 34 epidermal growth factor-like repeat domains (EGFrs). Participants will gene mutations in exons 1-6 are expected to demonstrate worsened cognition, MRI abnormality, biofluid NfL marker, functional capacity and symptomatic severity than participants having gene mutation in exons 7-34.

All mutations in the NOTCH3 CADASIL gene will be characterized and the frequency of each mutation will be tallied. Gene mutations that are present for the most participants will be determined.

Polygenic risk scores (PRS) for cerebral small vessel disease and dementia will be derived for each participant. We will derive PRSs for phenotypes in the data, such as worsened white matter hyperintensities or disabling headache. The best-fit PRS for each phenotype will be used to address how the PRS may impact the association of NOTCH3 canonical mutations with clinical, neuroimaging, and fluid markers of CADASIL and whether PRSs will add information to a predictive risk model to inform management of CADASIL.

Lifestyle risk factors for VCID (e.g., inactivity, obesity, heavy alcohol use, smoking, SES) and comorbid health conditions (e.g., hypertension, hyperlipidemia, hypercholesterolemia, atrial fibrillation, diabetes) may contribute to disease outcomes.