Several causative genes have been associated with AD-RP, including RHO, PRPF31, PRPH2, RP1, IMPDH1, PRPF8, NR2E3, snRNP200, KLHL7, CRX, PRPF3, TOPORS, ADIPOR1, ARL3, CA4, FSCN2, GUCA1B, HK1, IMPG1, KIF3B, NRL, PRPF4, PRPF6, RDH12, ROM1, RP9, SEMA4A, SPP2, and many others [6]. Here, IMPDH1 is linked to Alzheimer disease.