Perlman Susan L
David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Handb Clin Neurol. 2011;100:113-40. doi: 10.1016/B978-0-444-52014-2.00006-9.
The spinocerebellar ataxias (SCA) are a large group of inherited disorders affecting the cerebellum and its afferent and efferent pathways. Their hallmark symptom is slowly progressive, symmetrical, midline, and appendicular ataxia. Some may also have associated hyperkinetic movements (chorea, dystonia, myoclonus, postural/action tremor, restless legs, rubral tremor, tics), which may aid in differential diagnosis and provide treatable targets to improve performance and quality of life in these progressive, incurable conditions. The typical dominant ataxias with associated hyperkinetic movements are SCA1-3, 6-8, 12, 14, 15, 17, 19-21, and 27. The common recessive ataxias with associated hyperkinetic movements are ataxia telangiectasia and Friedreich's ataxia. Fragile X tremor-ataxia syndrome (FXTAS) and multiple-system atrophy (a sporadic ataxia which is felt to have a genetic substrate) also have hyperkinetic features. A careful work-up should be done in all apparently sporadic cases, to rule out acquired causes of ataxia, some of which can cause hyperkinetic movements in addition to ataxia. Some testing should be done even in individuals with a confirmed genetic cause, as the presence of a secondary factor (nutritional deficiency, thyroid dysfunction) can contribute to the phenotype.
脊髓小脑共济失调（SCA）是一大类遗传性疾病，影响小脑及其传入和传出通路。其标志性症状是缓慢进展的、对称性的、中线及肢体共济失调。部分患者还可能伴有运动亢进（舞蹈症、肌张力障碍、肌阵挛、姿势性/动作性震颤、不宁腿、红核震颤、抽动），这可能有助于鉴别诊断，并为改善这些进行性、无法治愈疾病的功能及生活质量提供可治疗的靶点。伴有运动亢进的典型显性共济失调包括SCA1-3、6-8、12、14、15、17、19-21和27型。伴有运动亢进的常见隐性共济失调包括共济失调毛细血管扩张症和弗里德赖希共济失调。脆性X震颤共济失调综合征（FXTAS）和多系统萎缩（一种被认为有遗传基础的散发性共济失调）也有运动亢进特征。对于所有明显散发的病例都应进行仔细检查，以排除获得性共济失调病因，其中一些除共济失调外还可导致运动亢进。即使对于已确诊有遗传病因的个体也应进行一些检测，因为存在次要因素（营养缺乏、甲状腺功能障碍）可能影响表型。
