Moreover, the over-expression of familial AD-associated presenilin 2 mutations (PS2 M239I and PS2 T122R) resulted in reduced levels of all cystatin C forms (native and glycosylated) and of amyloid-β precursor protein (APP) metabolites within exosomes.
In a family with autopsy-confirmed Alzheimer disease, the authors found a mutation in the presenilin 2 (PS2) gene (PSEN2) that predicts a methionine-to-isoleucine change at PS2 residue 239 (M239I), at which a change to valine was known in another family.