Hübers Annemarie, Marroquin Nicolai, Schmoll Birgit, Vielhaber Stefan, Just Marlies, Mayer Benjamin, Högel Josef, Dorst Johannes, Mertens Thomas, Just Walter, Aulitzky Anna, Wais Verena, Ludolph Albert C, Kubisch Christian, Weishaupt Jochen H, Volk Alexander E
Department of Neurology, University of Ulm, Ulm, Germany.
Institute of Human Genetics, University of Ulm, Ulm, Germany.
Neurobiol Aging. 2014 May;35(5):1214.e1-6. doi: 10.1016/j.neurobiolaging.2013.11.034. Epub 2013 Dec 4.
The GGGGCC-hexanucleotide repeat expansion in C9orf72 is the most common genetic cause of familial amyotrophic lateral sclerosis and frontotemporal dementia. This study determined the frequency of C9orf72 repeat expansions in different motor neuron diseases (amyotrophic lateral sclerosis (ALS), motor neuron diseases affecting primarily the first or the second motor neuron and hereditary spastic paraplegia). Whereas most studies on C9orf72 repeat expansions published so far rely on a polymerase chain reaction-based screening, we applied both polymerase chain reaction-based techniques and Southern blotting. Furthermore, we determined the sensitivity and specificity of Southern blotting of the C9orf72 hexanucleotide repeat in DNA derived from lymphoblastoid cell lines. C9orf72 repeat expansions were found in 27.1% out of 166 familial ALS patients, only once in 68 sporadic ALS patients, and not in 61 hereditary spastic paraplegia patients or 52 patients with motor neuron diseases affecting clinically primarily either the first or the second motor neuron. We found hints for a correlation between C9orf72 repeat length and the age of onset. Somatic instability of the C9orf72 repeat was observed in lymphoblastoid cell lines compared with DNA derived from whole blood from the same patient and therefore caution is warranted for repeat length determination in immortalized cell lines.
C9orf72基因中的GGGGCC六核苷酸重复序列扩增是家族性肌萎缩侧索硬化症和额颞叶痴呆最常见的遗传病因。本研究确定了C9orf72重复序列扩增在不同运动神经元疾病（肌萎缩侧索硬化症（ALS）、主要影响第一或第二运动神经元的运动神经元疾病以及遗传性痉挛性截瘫）中的发生频率。尽管迄今为止发表的大多数关于C9orf72重复序列扩增的研究都依赖基于聚合酶链反应的筛查，但我们同时应用了基于聚合酶链反应的技术和Southern印迹法。此外，我们还确定了从淋巴母细胞系衍生的DNA中C9orf72六核苷酸重复序列Southern印迹法的敏感性和特异性。在166例家族性ALS患者中，27.1%发现有C9orf72重复序列扩增，68例散发性ALS患者中仅1例发现，61例遗传性痉挛性截瘫患者或52例临床上主要影响第一或第二运动神经元的运动神经元疾病患者中均未发现。我们发现了C9orf72重复序列长度与发病年龄之间存在相关性的线索。与来自同一患者全血的DNA相比，在淋巴母细胞系中观察到C9orf72重复序列的体细胞不稳定性，因此在永生化细胞系中进行重复序列长度测定时需要谨慎。
