While the root cause of sporadic ALS is unknown, its common pathological hallmark is deposition of ubiquitin-positive cytoplasmic inclusions containing aggregated forms of DNA/RNA-binding protein TDP-43, encoded by the TARDBP gene, in the degenerating motor neurons (Arai et al., 2006; Neumann et al., 2006; Mackenzie et al., 2007). Here, TARDBP is linked to amyotrophic lateral sclerosis.