TREM2 and Alzheimer disease: However, it is unclear whether these protective effects result from an attenuated protein accumulation process that may be accelerated by microglia activation [4, 5, 28, 70, 72, 79, 85] in carriers of the mutated PLCG2 gene, or whether the response to accumulated protein aggregates is different, which is the suggested modus operandi for other AD-associated genes like TREM2 [34].