APOE, PSEN1, and MAPT are pathogenic genes which might influence the effects of memantine in AD, and variants in some mechanistic genes (GRIN2A, GRIN2B, GRIN3A, HTR3A, CHRFAM7A, c-Fos, Homer1b, and PSD-95) may also modify its therapeutic effects. Here, APOE is linked to Alzheimer disease.