In results from the ongoing, prospective, community-based Rotterdam study, for example, investigators showed that by combining assessments of parental history of AD along with APOE genotype (the major genetic risk factor for AD) and a genetic risk score aggregating 23 other genetic variants associated with the disease, they could identify a subset of individuals whose risk for developing AD by age 85 was greater than 90 percent (Dufouil and Glymour 2018; van der Lee et al. 2018). The gene discussed is APOE; the disease is Alzheimer disease.