SCA48 is a novel spinocerebellar ataxia (SCA) originally and recently characterized by prominent cerebellar cognitive-affective syndrome (CCAS) and late-onset ataxia caused by mutations on the STUB1 gene. Here, we report the first SCA48 case from Turkey with novel clinical features and diffusion tensor imaging (DTI) findings, used for the first time to evaluate a SCA48 patient. A 65-year-old female patient with slowly progressive cerebellar ataxia, cognitive impairment, behavioral changes, and a vertical family history was evaluated. Following the exclusion of repeat expansion ataxias, whole exome sequencing (WES) was performed. Brain magnetic resonance imaging (MRI), including DTI, and single-photon emission computed tomography (SPECT) were used to study the primarily affected tracts and regions. WES revealed the previously reported heterozygous truncating mutation in ubiquitin ligase domain of STUB1 (ENST00000219548:c.823_824delCT, ENSP00000219548:p.L275Dfs*16) leading to a frameshift. Patient’s cognitive status was compatible with CCAS. Novel clinical features different from the original report include later onset chorea, dystonia, general slowness of movements, apraxia, and palilalia, some of which have been recently reported in two families with different STUB1 mutations. CCAS is a prominent and often early feature of SCA48 which may be followed years after the onset of the disease by other complex neurological signs and symptoms. DTI may be helpful for demonstrating the cerebello-frontal tracts, involved in CCAS-associated SCA48, the differential diagnosis of which may be challenging especially in its early years.

中文翻译：

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共济失调前的小脑认知情感综合症与土耳其SCA48家族的复杂锥体外系特征相关。

SCA48是一种新颖的脊髓小脑共济失调（SCA），其最初特征是最近以突出的小脑认知情感综合症（CCAS）和STUB1突变引起的迟发性共济失调为特征基因。在这里，我们报道了土耳其的首例SCA48病例，该病例具有新颖的临床特征和弥散张量成像（DTI）发现，首次用于评估SCA48患者。评估了一名65岁女性患者，该患者患有缓慢进行性小脑共济失调，认知障碍，行为改变和垂直家族史。排除重复扩展共济失调后，进行全外显子组测序（WES）。脑磁共振成像（MRI）包括DTI和单光子发射计算机断层扫描（SPECT）用于研究主要受影响的区域和区域。WES揭示了先前报道的STUB1泛素连接酶结构域的杂合截短突变（ENST00000219548：c.823_824delCT，ENSP00000219548：p.L275Dfs * 16）导致移码。患者的认知状态与CCAS相符。与原始报道不同的新临床特征包括后来的舞蹈病，肌张力障碍，运动缓慢，失用和骨，其中一些最近在两个具有不同STUB1突变的家族中被报道。CCAS是SCA48的突出特征，通常是其早期特征，在疾病发作数年后，可能还会出现其他复杂的神经系统症状和体征。DTI可能有助于证实与CCAS相关的SCA48所涉及的小脑额叶区，尤其是在其早期，对其进行鉴别诊断可能会遇到挑战。