A nationwide survey of episodic ataxia in Japan

Abstract

AbstractBackgroundEpisodic ataxia (EA) is a rare inherited disorder characterized by recurrent cerebellar ataxic attacks. Given the limited number of EA case reports in Japan, the current status of EA medical conditions has become obscure, including the number of patients genetically confirmed to have EA and the clinical care these patients received.AimWe aimed to address the current status of EA medical conditions in Japan by investigating the total number of patients genetically confirmed to have the disease and their clinical characteristics.MethodsWe conducted a two‐step survey, primarily a nationwide survey using a round‐trip postcard for medical institutions expected to care for EA patients. As a secondary investigation, more detailed clinical information for each case was obtained using a written questionnaire. Furthermore, we explored the literature, including EA case reports in Japan.ResultsOur survey showed the clinical information of 20 EA type 2 (EA2) cases from 14 pedigrees, as confirmed by genetic analysis. In addition to cerebellar ataxic symptoms, clinical manifestations of the included patients were broad, including dizziness, balance disturbance, headache, epilepsy, and psychomotor developmental delay.ConclusionThe number of patients with genetically confirmed EAs is currently limited in Japan, and a significant number of them may remain undiagnosed. We believe that the development of diagnostic strategies for EA has clinical benefits.