Penetrance, or the extent to which a genetic variant or set of variants were observed in individuals with Alzheimer's disease and recurrence risk, or the probability of an inherited disorder such as Alzheimer's disease in one family member will occur again in other family members were estimated using PRS and compared with similar analyses using APOE‐ε4 allele alone. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.