Of the several other genes that have been associated with ALS (29), three encode proteins important for microtubule-based cargo transport: the tubulin isotype α4a (30), the plus end-directed kinesin-1 motor KIF5A (31), and DCTN1, a component of the dynactin complex that activates the minus end-directed motor cytoplasmic dynein-1 (hereafter dynein) (32). This evidence concerns the gene KIF5A and amyotrophic lateral sclerosis.