SPAST and amyotrophic lateral sclerosis: Currently, only eight key cytoskeleton-related genes are directly implicated in ALS, including α-tubulin (TUBA4A), SPAST (spastin), KIF5A (kinesin family member 5A), dynactin-1 (DCTN1), NF (neurofilament), PRPH (peripherin), alsin (ALS2), and PFN1 (profilin).