Whereas this patient died at the age of 23, the only known reported patient with the same TARDBP mutation died at the age of 63 so it may simply be that the FUS mutation is the more “aggressive” mutation and they act independently such that we are seeing the end stage of the FUS-ALS disease and the earliest (if any) stage of the ALS-TDP disease [18]. This evidence concerns the gene TARDBP and amyotrophic lateral sclerosis.