ATL1 and proximal spinal muscular atrophy: Specific disturbances of LD movement or tethering have been linked to congenital disorders of autophagy, including SNX14‐related spinocerebellar ataxia, BICD2‐related spinal muscular atrophy, and several forms of hereditary spastic paraplegia including SPG3A/ATL1, SPG4/SPAST, SPG11/KIAA1840, and SPG20/SPART.27