GRN and amyotrophic lateral sclerosis: It is also involved in the delivery of progranulin to the lysosome for degradation, therefore contributing to the loss of progranulin which leads to frontotemporal dementia and TDP-43 pathology in ALS (Hu et al., 2010; Kumar-Singh, 2011; Carlo, Nykjaer, and Willnow, 2014; Gan, Khan, and Gitcho, 2015).