Mutations in Trk-fused gene (TFG) and tectonin beta-propeller repeat-containing protein 2 (TECPR2), proteins that associate with COPII and help mediate ER-to-Golgi transport, also cause HSP, indicating that defective trafficking in the early secretory pathway can also cause this type of disorder (Beetz et al., 2013; Stadel et al., 2015). This evidence concerns the gene TECPR2 and hereditary spastic paraplegia.