In a mouse model of amyloidosis, human wild-type TREM2 kept Aβ deposition at bay early on, but this defense became overwhelmed as plaques grew. The R47H AD risk variant never offered protection early on, and made things worse later.
For people with Parkinson’s, carrying Alzheimer’s genetic risk variants upped their odds of harboring Aβ and tau pathology and getting dementia. In people with DLB, Aβ plaques worsened tau and Lewy pathology, and cognition.