It is interesting to note that the gene for ALDH18A1 (Delta-1-Pyrroline-5-Carboxylate Synthase), a condition with symptoms comparable to those of people with PSEN1(A431E) mutation, is associated with spastic paraplegias (SPG9A and SP9B) [144]. Here, ALDH18A1 is linked to Spastic paraplegia.