[Geographic Distribution of Patients with CADASIL in Japan]

CADASIL, a hereditary cerebral small vessel disease, is caused by mutations in the NOTCH3 gene. We analyzed 908 patients whose genetic testing was performed at Kyoto Prefectural University of Medicine (KPUM) from 1999 to March 2024, focusing on geographic area and the department requesting the genetic test. We found that the number of requests and positive results were influenced by geographic distance from KPUM. Most requests were from the Department of Neurology, whereas only 1.9% were from neurosurgery. Mutations of high frequency were identified in almost all areas in Japan. Mutations tended to more varied in Eastern than in Western Japan. To increase recognition of the diagnosis cases, it is important to increase awareness of the diagnosis by stroke specialists, in both neurology and neurosurgery.