Spastic paraplegia (SP) was a quite common phenotype and is related to EOAD with PSEN1 mutations, for example Tyr154Asn, Phe237Ile, Pro264Leu and Glu280Gly, or mutations related to the abnormal splicing of exon 9 (Table 3). The gene discussed is PSEN1; the disease is Spastic paraplegia.