Heterozygous missense mutations in the N-terminal motor or coiled-coil domains of the kinesin family member 5A (KIF5A) gene cause monogenic spastic paraplegia (HSP10) and Charcot-Marie-Tooth disease type 2 (CMT2). Moreover, heterozygous de novo frame-shift mutations in the C-terminal domain of KIF5A are associated with neonatal intractable myoclonus, a neurodevelopmental syndrome. These findings, together with the observation that many of the disease genes associated with amyotrophic lateral sclerosis disrupt cytoskeletal function and intracellular transport, led us to hypothesize that mutations in KIF5A are also a cause of amyotrophic lateral sclerosis. Using whole exome sequencing followed by rare variant analysis of 426 patients with familial amyotrophic lateral sclerosis and 6137 control subjects, we detected an enrichment of KIF5A splice-site mutations in amyotrophic lateral sclerosis (2/426 compared to 0/6137 in controls; P = 4.2 × 10-3), both located in a hot-spot in the C-terminus of the protein and predicted to affect splicing exon 27. We additionally show co-segregation with amyotrophic lateral sclerosis of two canonical splice-site mutations in two families. Investigation of lymphoblast cell lines from patients with KIF5A splice-site mutations revealed the loss of mutant RNA expression and suggested haploinsufficiency as the most probable underlying molecular mechanism. Furthermore, mRNA sequencing of a rare non-synonymous missense mutation (predicting p.Arg1007Gly) located in the C-terminus of the protein shortly upstream of the splice donor of exon 27 revealed defective KIF5A pre-mRNA splicing in respective patient-derived cell lines owing to abrogation of the donor site. Finally, the non-synonymous single nucleotide variant rs113247976 (minor allele frequency = 1.00% in controls, n = 6137), also located in the C-terminal region [p.(Pro986Leu) in exon 26], was significantly enriched in familial amyotrophic lateral sclerosis patients (minor allele frequency = 3.40%; P = 1.28 × 10-7). Our study demonstrates that mutations located specifically in a C-terminal hotspot of KIF5A can cause a classical amyotrophic lateral sclerosis phenotype, and underline the involvement of intracellular transport processes in amyotrophic lateral sclerosis pathogenesis.

中文翻译：

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热点KIF5A突变会导致家族性ALS。

驱动蛋白家族成员5A（KIF5A）基因的N末端运动或螺旋卷曲域中的杂合错义突变导致单基因痉挛性截瘫（HSP10）和Charcot-Marie-Tooth疾病2型（CMT2）。此外，KIF5A的C末端域中的杂合的de novo移码突变与新生儿难治性肌阵挛（一种神经发育综合征）有关。这些发现以及与肌萎缩性侧索硬化症相关的许多疾病基因破坏细胞骨架功能和细胞内转运的观察结果，使我们推测KIF5A突变也是肌萎缩性侧索硬化症的原因。使用全外显子组测序，然后对426例家族性肌萎缩性侧索硬化症患者和6137例对照受试者进行罕见的变异分析，我们在肌萎缩性侧索硬化症中检测到丰富的KIF5A剪接位点突变（2/426，对照组为0/6137； P = 4.2×10-3），均位于蛋白C端的热点并预计会影响剪接外显子27。我们另外显示了两个家族中两个典型的剪接位点突变与肌萎缩性侧索硬化的共分离。对来自具有KIF5A剪接位点突变的患者的淋巴母细胞细胞系的研究揭示了突变RNA表达的丧失，并提示单倍剂量不足是最可能的潜在分子机制。此外，罕见的非同义错义突变的mRNA测序（预测p。位于外显子27剪接供体上游不久的蛋白质C末端的Arg1007Gly）由于供体位点的废除，在相应的患者衍生细胞系中发现了有缺陷的KIF5A pre-mRNA剪接。最后，同样位于C末端区域[外显子26的p。（Pro986Leu）]的非同义单核苷酸变体rs113247976（次要等位基因频率= 1.00％，对照，n = 6137）在家族肌萎缩症中显着富集。侧索硬化症患者（次等位基因频率= 3.40％； P = 1.28×10-7）。我们的研究表明，具体位于KIF5A的C末端热点的突变可引起经典的肌萎缩性侧索硬化症表型，并强调了肌内萎缩性侧索硬化症发病机理中的细胞内转运过程。非同义的单核苷酸变体rs113247976（在对照组中次等位基因频率= 1.00％，n = 6137），也位于C末端区域[外显子26中的p。（Pro986Leu）]，在家族性肌萎缩性侧索硬化症中显着丰富患者（次等位基因频率= 3.40％； P = 1.28×10-7）。我们的研究表明，具体位于KIF5A的C末端热点的突变可引起经典的肌萎缩性侧索硬化症表型，并突显了肌萎缩性侧索硬化症发病机理中的细胞内转运过程。非同义的单核苷酸变体rs113247976（在对照组中次等位基因频率= 1.00％，n = 6137），也位于C末端区域[外显子26中的p。（Pro986Leu）]，在家族性肌萎缩性侧索硬化症中显着丰富患者（次等位基因频率= 3.40％； P = 1.28×10-7）。我们的研究表明，具体位于KIF5A的C末端热点的突变可引起经典的肌萎缩性侧索硬化症表型，并突显了肌萎缩性侧索硬化症发病机理中的细胞内转运过程。在家族性肌萎缩性侧索硬化患者中明显丰富（次要等位基因频率= 3.40％； P = 1.28×10-7）。我们的研究表明，具体位于KIF5A的C末端热点的突变可引起经典的肌萎缩性侧索硬化症表型，并突显了肌萎缩性侧索硬化症发病机理中的细胞内转运过程。在家族性肌萎缩性侧索硬化患者中明显丰富（次要等位基因频率= 3.40％； P = 1.28×10-7）。我们的研究表明，具体位于KIF5A的C末端热点的突变可引起经典的肌萎缩性侧索硬化症表型，并突显了肌萎缩性侧索硬化症发病机理中的细胞内转运过程。