PSEN2 and early-onset autosomal dominant Alzheimer disease: For Alzheimer’s disease, the most substantial kindred of PSEN1 was in Colombia, with multiple other genetic presentations of familial Alzheimer’s disease.94-102 Different alleles and mutations in genes such as PSEN1, PSEN2, PICALM, and BIN1, among others, were associated with Alzheimer’s disease to varying degrees.103,104 Strong associations between the APOE ε4 allele and an increased risk of Alzheimer’s disease were accompanied by a protective effect of APOE ε2.