Alleles in the TREM2 gene have been associated with a three to five times higher risk of developing Alzheimer's disease.[61]

A Japanese pedigree of familial Alzheimer's disease was found to be associated with a deletion mutation of codon 693 of APP.[62] This mutation and its association with Alzheimer's disease was first reported in 2008,[63] and is known as the Osaka mutation. Only homozygotes with this mutation have an increased risk of developing Alzheimer's disease. This mutation accelerates Aβ oligomerization but the proteins do not form the amyloid fibrils that aggregate into amyloid plaques, suggesting that it is the Aβ oligomerization rather than the fibrils that may be the cause of this disease. Mice expressing this mutation have all the usual pathologies of Alzheimer's disease.[64]