Oligodendrocyte myelin glycoprotein (OMG) is a brain-specific protein implicated in myelination, but its potential mechanistic, biomarker, and therapeutic roles in ADRDs requires further elucidation.<h4>Methods</h4>After detecting an inverse association between its abundance in peripheral circulation and cortical amyloid deposition in two community-based cohorts, the current study characterized OMG's role in ADRDs with high-throughput proteomics from sixteen independent cohorts. Here, OMG is linked to amyloidosis.