For example, pathogenic variants of the anterograde and retrograde motors or associated proteins KIF5A and dynactin subunit 1 (DCTN1; p150Glued) both disrupt axonal transport [50, 51], and ALS-associated variants of the heavily phosphorylated repeat region of the heavy neurofilament subunit (NEFH) are likely to cause axonal swellings [52]. This evidence concerns the gene NEFH and amyotrophic lateral sclerosis.