Yield of screening for CADASIL mutations in lacunar stroke and leukoaraiosis

Background and Purpose - Cerebral autosomal dominant arteriopathy subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic disorder typified by early onset lacunar strokes, subcortical dementia, psychiatric disturbances, and migraine. Mutations in the Notch3 gene are responsible. Atypical phenotypes have been recognized, and the disease is probably underdiagnosed in the wider stroke population. Therefore, we determined the yield of screening for Notch3 mutations in lacunar stroke with or without leukoaraiosis. Methods - Two hundred eighteen consecutive patients were studied. All had brain and carotid imaging. Polymerase chain reaction-single-stranded conformational polymorphism analysis was used to screen exons 3, 4, 5, and 6 of the Notch3 gene for mutations and polymorphisms. Results - A single mutation in exon 4 (C697T) was identified in a young patient, giving an overall carrier frequency of 0.05% (95% CI, 0.0 to 2.0). For patients with onset of lacunar stroke at ≤65 years and leukoaraiosis, the yield was 2.0% (95% CI, 0.4 to 10.9). Conclusions - Notch3 mutations are rare in patients with typical strokes due to cerebral small-vessel disease. In the absence of classic features suggestive of CADASIL, screening for Notch3 mutations has a low yield.