Mutation in DYNC1H1, classified by the ALSoD database as an ALS gene, have been previously associated with autosomal dominant CMT type 2O but also with spinal muscular atrophy with a predominance of lower extremity involvement (SMA-LED), HSP, and hereditary mental retardation with cortical neuronal migration defects [59,60,61]. This evidence concerns the gene DYNC1H1 and proximal spinal muscular atrophy.