PSEN2 and Alzheimer disease: The key role of genetic factors in the development of AD isevidenced by the presence of monogenic hereditary forms ofthe disease with an autosomal dominant type of inheritance.These forms of the disease are caused by germline mutationsin the APP (amyloid precursor protein) (Rogaev et al., 1994;Goate et al., 2006), PSEN1 (presenilin-1) (Sherrington etal., 1995), PSEN2 (presenilin-2) (Levy-Lahad et al., 1995)genes.