Notably, we identified double mutations in a 52-year-old female (PSEN2 p.M239I and MAPT p.R5H), but her daily living ability remained intact, and the double mutation did not accelerate the cognitive decline, further expanding the phenotype spectrum of the mutation and supporting the phenotypic heterogeneity among subjects carrying the same MAPT mutations. This evidence concerns the gene PSEN2 and Mental deterioration.