講演情報
[O10-5]北海道における常染色体顕性遺伝（優性遺伝）性脊髄小脳変性症の疾患構成
○柴田 有花1, 松島 理明1,2, 江口 克紀2,3, 長井 梓2, 脇田 雅大2,4, 矢部 一郎1,2 (1.北海道大学病院 臨床遺伝子診療部, 2.北海道大学 大学院医学研究院 神経病態学分野 神経内科学教室, 3.医療法人北祐会 北海道脳神経内科病院, 4.日本赤十字社 旭川赤十字病院)
[Introduction] In Japan, approximately 30% of Spinocerebellar degeneration (SCD) are hereditary, and more than 90% of them are autosomal dominant cerebellar ataxias (AD-SCA). We have previously reported the disease constitutions of AD-SCA in Hokkaido, twice. We investigated current status of the disease constitutions since the last report. [Methods] We performed genetic analysis for 316 patients with a clinical diagnosis of SCD except for multiple system atrophy at medical institutions in Hokkaido between January 2007 and December 2020. [Results] The mean age at the time of analysis was 55.6 (1-86) years. Pathogenic variants were found in 199 cases (63.0%). Spinocerebellar ataxia type 6 (SCA6) was the most common type in 80 cases (25.3%), Machado-Joseph disease (MJD)/SCA3 in 43 (13.6%), SCA1 in 20 (6.3%), SCA2 in 16 (5.1%), SCA31 in 15 (4.8%), Dentatorubral- pallidoluysian atrophy in 15 (4.8%), SCA42 in 5 (1.6%), SCA7 in 2 (0.6%), SCA8 in 2 (0.6%), and SCA14 in 1 (0.3%). Patients with family history tended to be younger than those without family history (p=0.087). 37.0% of the patients had no pathogenic variant in the primary causing gene. [Discussion] Compared to previous reports, SCA6 had the higher percentage and MJD/SCA3 had the lower percentage. This may be due to the fact that in older-onset disease with no clear family history, such as SCA6, genetic analysis was performed more frequently for diagnosis than with a clear family history. Further genetic analysis studies should be conducted for SCD cases for which pathogenic variants have not yet been identified.