More than 15 mouse models have been reported in which WT and ALS mutant of human TDP-43 are exogenously expressed [48], but the disease relevance of these systems to ALS is uncertain because of the considerable variability in the observed motor phenotypes, and the overexpression of WT as well as mutant TDP-43 leads to a similar motor phenotype [49]. The gene discussed is TARDBP; the disease is amyotrophic lateral sclerosis.