Shindo Kazumasa, Sato Tohko, Murata Hiroaki, Ichinose Yuta, Hata Takanori, Takiyama Yoshihisa
Department of Neurology, University of Yamanashi, 1110 Shimokatou, Yamanashi, 409-3898, Japan.
BMC Neurol. 2019 Jan 11;19(1):9. doi: 10.1186/s12883-019-1238-1.
Spinocerebellar ataxia type 31 (SCA 31) is a slowly progressive neurodegenerative disorder characterized by pure cerebellar ataxia. Unlike other CAG repeat diseases, sleep-related problems have not been reported in patients with SCA 31 so far.
A 67-year-old woman was admitted to our hospital with dysarthria and gait disturbance after onset age of 62 years. Neurological examination revealed pure cerebellar ataxia. Genetic analysis detected expansion of a TGGAA repeat in the coding region of the BEAN/TK2 gene on chromosome 16p22.1, confirming the diagnosis of SCA 31. One year later, her husband noticed the patient talking loudly during sleep once or twice a week. Overnight polysomnography showed rapid eye movement sleep without atonia. Cardiac scintigraphy with iodine-123-labeled meta-iodobenzylguanidine revealed a low heart/mediastinum ratio, indicating reduced uptake, and a high washout rate.
To our knowledge, this is the first report of a patient with SCA 31 associated with rapid eye movement sleep behavior disorder (RBD). In the future, evaluation of autonomic function, assessment of the frequency of RBD, and performance of cardiac iodine-123-labeled meta-iodobenzylguanidine scintigraphy in a larger number of SCA 31 patients could be useful to resolve important issues regarding the mechanism of RBD.
31型脊髓小脑共济失调（SCA 31）是一种以单纯小脑性共济失调为特征的缓慢进展性神经退行性疾病。与其他CAG重复疾病不同，目前尚未有SCA 31患者出现睡眠相关问题的报道。
一名67岁女性在62岁发病后因构音障碍和步态障碍入院。神经系统检查显示为单纯小脑性共济失调。基因分析检测到16号染色体p22.1上BEAN/TK2基因编码区的TGGAA重复序列扩增，确诊为SCA 31。一年后，她的丈夫注意到患者每周有一两次在睡眠中大声说话。夜间多导睡眠图显示快速眼动睡眠期无肌张力缺失。用碘-123标记的间碘苄胍进行心脏闪烁扫描显示心/纵隔比值低，提示摄取减少，且洗脱率高。
据我们所知，这是首例与快速眼动睡眠行为障碍（RBD）相关的SCA 31患者报告。未来，对大量SCA 31患者进行自主神经功能评估、RBD频率评估以及心脏碘-123标记的间碘苄胍闪烁扫描，可能有助于解决有关RBD机制的重要问题。
