Late-Onset Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy (CADASIL) Presenting With Abnormal MRI Findings and Migraine: A Case Report.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small-vessel disease caused by mutations in the NOTCH3 gene. It typically presents in mid-adulthood with migraine with aura, recurrent ischemic strokes or transient ischemic attacks, and progressive cognitive decline. Late-onset presentations are uncommon and may pose diagnostic challenges due to atypical clinical features. We report a case of late-onset CADASIL in a patient who initially presented with intermittent migraine and abnormal MRI findings. Neuroimaging revealed extensive white matter hyperintensities involving the periventricular and deep white matter, as well as the external capsules and the corpus callosum, raising suspicion of CADASIL. Genetic testing confirmed a pathogenic variant in the NOTCH3 gene. This case highlights the importance of considering CADASIL in older patients with unexplained MRI abnormalities and migraine, even in the absence of classic early symptoms. Early diagnosis is essential for appropriate management, family screening, and avoidance of unnecessary interventions.