MAPT and posterior cortical atrophy: However, the PCA phenotype has rarely been described in association with genetic mutations known to be implicated in familial AD, [PSEN1 (88, 89) and PSEN2 (90)], mutations associated with frontotemporal dementia [MAPT (91) and GRN genes (8)], as well as in the gene of the prion protein (PRNP) (92).