They delineated four different subtypes of AD pathology: (1) subtype 1, wherein tau protein is mainly deposited in the temporal cortex, affecting memory, accounting for 33%; (2) subtype 2, wherein tau protein is mainly deposited in the occipital cortex, affecting visual–spatial processing, accounting for 30%; (3) subtype 3, wherein tau protein spreads asymmetrically in the left brain, affecting language ability, accounting for 19%; and (4) subtype 4, wherein tau protein deposits and spreads in other parts of the cerebral cortex, affecting executive function, accounting for 18%. This evidence concerns the gene MAPT and Alzheimer disease.