High frequency ofHTRA1ANDABCC6mutations in Japanese patients with adult-onset cerebral small vessel disease

BackgroundThis study aimed to clarify the frequency and clinical features of monogenic cerebral small vessel disease (mgCSVD) among patients with adult-onset severe CSVD in Japan.MethodsThis study included patients with adult-onset severe CSVD with an age of onset ≤55 years (group 1) or >55 years and with a positive family history (group 2). After conducting conventional genetic tests forNOTCH3andHTRA1, whole-exome sequencing was performed on undiagnosed patients. Patients were divided into two groups according to the results of the genetic tests: monogenic and undetermined. The clinical and imaging features were compared between the two groups.ResultsGroup 1 and group 2 included 75 and 31 patients, respectively. In total, 30 patients hadNOTCH3mutations, 11 patients hadHTRA1mutations, 6 patients hadABCC6mutations, 1 patient had aTREX1mutation, 1 patient had aCOL4A1mutation and 1 patient had aCOL4A2mutation. The total frequency of mutations inNOTCH3,HTRA1andABCC6was 94.0% in patients with mgCSVD. In group 1, the frequency of a family history of first relatives, hypertension and multiple lacunar infarctions (LIs) differed significantly between the two groups (monogenic vs undetermined; family history of first relatives, 61.0% vs 25.0%, p=0.0015; hypertension, 34.1% vs 63.9%, p=0.0092; multiple LIs, 87.8% vs 63.9%, p=0.0134).ConclusionsMore than 90% of mgCSVDs were diagnosed by screening forNOTCH3,HTRA1andABCC6. The target sequences for these three genes may efficiently diagnose mgCSVD in Japanese patients.