[Skin Biopsy is a Useful Tool for the Diagnosis of Atypical CADASIL: A Case Report]

A 57-year-old man developed migraine at the age of 25 years. Thereafter, he developed depression at the age of 50 years, and was admitted to a psychiatric hospital at the age of 54 years because of deteriorating depression. He returned to his work after receiving treatment for depression; however, he made mistakes several times in his work. He was referred to our hospital for further neurological evaluation. The results of the neurological examination performed on admission were unremarkable. His Mini Mental State Examination (MMSE) score was 24/30, and neuropsycological evaluations revealed executive dysfunction. There was no family history of dementia or cerebral infarction. Magnetic resonance fluid attenuated inversion recovery (MR FLAIR) image of the brain showed hyperintense lesions around the lateral ventricle without involvement in the temporal pole and external capsule. Despite a lack of family history of dementia and cerebral infarction and non-specific brain MRI findings, his history of headache and depression were suggestive of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Therefore, skin biopsy was performed; electron microscopy of the biopsied sample revealed granular osmiophilic material deposits. Genetic analysis of the NOTCH3 gene showed a missense mutation with substitution of R427C in exon 8, i.e., out of the hot-spot, exon 3, and 4. Thus, skin biopsy is a useful tool for diagnosing atypical CADASIL.