To evaluate the overall relevance of HNRNPK localization in C9orf72 ALS, we used two independent patient models (i.e., C9orf72 ALS patient fibroblasts, iPSC-derived motor neurons) and post-mortem tissue to demonstrate that HNRNPK localization is mislocalized to the cytoplasm in C9orf72 ALS, as was recently shown for FTD [4]. Here, C9orf72 is linked to amyotrophic lateral sclerosis.