Molecular mechanisms of the genetic risk factors in pathogenesis of Alzheimer disease.

Alzheimer disease (AD) is a neurodegenerative disease characterized by the extensive deposition of senile plaques and neurofibrillary tangles. Until recently, only the APOE gene had been known as a genetic risk factor for late-onset AD (LOAD), which accounts for more than 95% of all AD cases. However, in addition to this well-established genetic risk factor, genome-wide association studies have identified several single nucleotide polymorphisms as genetic risk factors of LOAD, such as PICALM and BIN1. In addition, whole genome sequencing and exome sequencing have identified rare variants associated with LOAD, including TREM2. We review the recent findings related to the molecular mechanisms by which these genetic risk factors contribute to AD, and our perspectives regarding the etiology of AD for the development of therapeutic agents.