PER2 and early-onset autosomal dominant Alzheimer disease: Heat Shock Protein Family A (Hsp70) Member 1B (Hspa1b) and DnaJ Heat Shock Protein Family (Hsp 40) Member B1 (Dnajb1) genes are involved in Protein processing in endoplasmic reticulum pathway, Insulin Degrading Enzyme (Ide), Activity Regulated Cytoskeleton Associated Protein (Arc) and Period Circadian Regulator 2 (Per2) genes are related to Alzheimer’s disease, Amphetamine addiction and Circadian entrainment pathways respectively.