KIF5A and hereditary spastic paraplegia: Among these, the anterograde axonal transport motor KIF5A stands out as a risk factor for the survival of long axons in multiple disorders, including hereditary spastic paraplegia (HSP) [95], Charcot-Marie-Tooth (CMT) disease Type 2 [96], adult onset distal SMA [97], and possibly neonatal intractable myoclonus [98], although whether this last one involves axon loss is less clear.