In the primary motor neurons, over-expression of WT TDP-43 or its ALS-associated mutants (Q331K and M337V) shortens the mitochondrial length and affects mitochondrial movement, which could be avoided by the co-expression of the mitochondrial fusion protein, mitofusin-2 (Mfn2) [113]. This evidence concerns the gene TARDBP and amyotrophic lateral sclerosis.