SYNE1 ataxia is an autosomal recessive hereditary condition, the main characteristic features of which are gait and limb ataxia and cerebellar dysarthria. Reports have revealed that the clinical phenotype of SYNE1 ataxia is more complex than the first published cases with pure cerebellar signs indicated. The aim of this study was to characterize eye movement alterations in the first diagnosed Hungarian SYNE1 ataxia patients. Saccades and antisaccades were examined with an eye tracker device in 3 SYNE1 (one patient has two frameshift mutations [c.8515_8516insA, p.Met2839Asnfs*53 and c.11594_11595insG, p.Glu3866*] in a compound heterozygous state, whereas two subjects have a splicing variant [c.23146-2A > G] in a homozygous state), 6 Friedreich ataxia (FA) patients and 12 healthy controls. Besides that, detailed clinical phenotyping and comprehensive neuropsychological assessment were carried out in all patients with ataxia. In addition to the characteristic cerebellar alterations, pyramidal signs and polyneuropathy were observed at least in 2 SYNE1 ataxia patients, for which no other underlying reason was found. The eye tracking assessment revealed hypometric saccades in the longer amplitude (18.4°) saccadic paradigm in all SYNE1 patients, whereas 2 out of 3 SYNE1 subjects performed slow saccades as well. In the antisaccade task, higher incorrect ratios of antisaccades were demonstrated in SYNE1 patients compared to healthy controls, showing inverse correlation with working memory test results. The corresponding data of FA patients was dispersed over a wide range, partially overlapping with control data. The current study draws attention to the presence of eye movement disorders in patients with SYNE1 ataxia and demonstrates that alterations in the antisaccade paradigm may be related to working memory deficits.

中文翻译：

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SYNE1 共济失调患者的眼动追踪辅助特征：一项初步研究

SYNE1共济失调是一种常染色体隐性遗传病，其主要特征是步态和肢体共济失调以及小脑构音障碍。报告显示，SYNE1 共济失调的临床表型比最初发表的具有纯小脑体征的病例更为复杂。本研究的目的是表征第一批诊断出的匈牙利 SYNE1 共济失调患者的眼球运动变化。在 3 个 SYNE1（一名患者有两个移码突变 [c.8515_8516insA、p.Met2839Asnfs*53 和 c.11594_11595insG、p.Glu3866*]）中，用眼动仪设备检查了眼跳和反跳视情况，而复合二杂合子受试者具有纯合状态下的剪接变体 [c.23146-2A > G]、6 名弗里德赖希共济失调 (FA) 患者和 12 名健康对照。除此之外，对所有共济失调患者进行了详细的临床表型分析和全面的神经心理学评估。除了特征性的小脑改变外，至少在 2 名 SYNE1 共济失调患者中观察到锥体体征和多发性神经病，没有发现其他潜在原因。眼动追踪评估显示所有 SYNE1 患者在较长幅度 (18.4°) 扫视范式中进行低度扫视，而 3 名 SYNE1 受试者中有 2 名也进行慢速扫视。在 antisaccade 任务中，与健康对照相比，SYNE1 患者的 antisaccades 错误率更高，与工作记忆测试结果呈负相关。FA患者的相应数据分布范围很广，与对照数据部分重叠。