Possible association of crossed cerebellar diaschisis with cerebellar ataxia in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

We report a 50‐year‐old man with no history of stroke or migraine, who developed progressive gait ataxia and dementia. MRI showed diffuse leukoencephalopathy, multiple lacunar lesions, and cerebellar atrophy. Ischemic lesions were absent in the cerebellum. On SPECT, crossed cerebellar diaschisis (CCD) was seen. Genetic testing confirmed the diagnosis of cerebral autosomal‐dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with a heterozygous NOTCH3 mutation p.Arg182Cys. His cerebellar dysfunction may have been caused by CCD due to interruption of cerebral‐cerebellar connections. Our case showed that CCD could be important for cerebellar function in CADASIL.