Hexanucleotide repeat expansions (HREs) in C9orf72 are a major cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). We aimed to determine the frequency and phenomenology of movement disorders (MD) in carriers of HRE in C9orf72 through a retrospective review of patients' medical records.

We retrospectively reviewed the clinical records of patients carrying a C9orf72 HRE in the pathogenic range and compared the characteristics of patients with and without MD.

Seventeen of 40 patients with a C9orf72 HRE had a documented MD. In 6 of 17, MD were the presenting symptom, and in 2 of 17, MD were the sole manifestation of the disease. FTD was present in 13 of 17 patients, ALS in 5 of 17 patients, and 2 of 17 patients did not develop FTD or ALS. Thirteen of 17 patients had more than one MD. The most common MD were parkinsonism and tremor (resembling essential tremor syndrome), each one present in 11 of 17 patients. Distal, stimulus-sensitive upper limbs myoclonus was present in 6 of 17 patients and cervical dystonia in 5 of 17 patients. Chorea was present in 5 of 17 patients, 4 of whom showed marked orofacial dyskinesias. The most frequent MD combination was tremor and parkinsonism, observed in 8 of 17 patients, 5 of whom also had myoclonus. C9orf72 patients without MD had shorter follow-up times and higher proportion of ALS, although these results did not survive the correction for multiple comparisons.

MD are frequent in C9orf72. They may precede signs of ALS or FTD, or even be present in isolation. Parkinsonism, tremor, and myoclonus are most commonly observed.

六核苷酸重复扩张（的HRE）中C9orf72是额颞叶痴呆（FTD）和肌萎缩侧索硬化（ALS）的主要原因。我们旨在通过回顾性回顾患者的病历来确定C9orf72中HRE携带者的运动障碍（MD）的频率和现象。

我们回顾性地研究了在致病性范围内携带C9orf72 HRE的患者的临床记录，并比较了有或没有MD的患者的特征。

40名C9orf72 HRE患者中有17名有记录的MD。17例中有6例是MD的症状，17例中有2例是MD的唯一​​表现。17例患者中有13例存在FTD，17例患者中有5例存在ALS，17例患者中有2例未发展为FTD或ALS。17例患者中有13例患有多于1例MD。最常见的MD是帕金森氏症和震颤（类似于原发性震颤综合征），每17例患者中有1例存在。远端刺激敏感的上肢肌阵挛出现在17例患者中的6例中，而宫颈肌张力障碍则在17例患者中的5例中。在17例患者中有5例存在舞蹈症，其中4例表现出明显的口面部运动障碍。MD的最常见组合是震颤和帕金森综合症，在17例患者中有8例观察到，其中5例也患有肌阵挛。C9orf72 没有MD的患者随访时间较短且ALS比例较高，尽管这些结果在多次比较的校正后均未幸免。

MD在C9orf72中很常见。它们可能先于ALS或FTD的征兆，甚至孤立地存在。帕金森氏症，震颤和肌阵挛最常见。