ALS2 and proximal spinal muscular atrophy: Several genes in ALS are known to cause many other neurodegenerative diseases, such as alsin with PLS and infantile onset ascending hereditary spastic paralysis (IAHSP), Senataxin with SCAR1 or AOA2, spatacsin with HSP, VAPB with SMA, FIG 4 with CMT type 4 J, OPTN with primary open angle glaucoma.