C9orf72 and amyotrophic lateral sclerosis: Consequently, reduced levels of the transcript variants have been reported in blood lymphocytes (Ciura et al., 2013), induced pluripotent stem cells (iPSCs)-derived neurons (Shi et al., 2018) and post mortem tissue of C9orf72-related ALS and FTD patients (van Blitterswijk et al., 2013b).