Some researchers have proposed a CADASIL severity grading system that encompasses five levels: grade 0 (absence of symptoms), grade 1 (migraine alone), grade 2 (stroke, TIA, or mild cognitive impairment), grade 3 (requiring walking assistance or dementia), and grade 4 (bedridden or advanced stage) for patients with known pathogenic NOTCH3 mutations, characteristic ischemic lesions on brain MRI, or characteristic intravascular deposits on skin biopsy (106). Here, NOTCH3 is linked to Stroke.