Another example, (Selvaraj et al., 2018) found, through a combination of RNA sequencing and electrophysiological studies, that repeated amplification of the C9ORF72 gene resulted in increased expression of the GluA1 AMPA receptor subunit, making motor neurons more sensitive to Ca2 + −permeable AMPA receptor-mediated excitotoxicity, a finding that, from the point of view of neuronal cellular signaling pathways reveals new potential triggers for ALS production, which is important for understanding disease progression and developing neuroprotective strategies. Here, C9orf72 is linked to amyotrophic lateral sclerosis.