PPARGC1A and Alzheimer disease: This led to the identification of 3 novel genes associated with AD; these genes are PPARGC1A, RORA and ZNF423. There is evidence that these genes are credible candidates in AD, with PPARGC1A and RORA being linked to circadian rhythm, PPARGC1A is implicated in energy metabolism and the generation of amyloid plaques, RORA is linked to cholesterol metabolism and inflammation and ZNF423 is likely involved in DNA damage repair and resides in an AD-specific protein network.