TREM2 and early-onset autosomal dominant Alzheimer disease: We recently demonstrated that common variants in MS4A4A are a trans-pQTL for CSF soluble TREM2 (sTREM2) levels and are associated with Alzheimer’s disease (AD) risk4, indicating that MS4A4A modifies risk for AD by modifying TREM2 biology, and that MS4A4A is a potential therapeutic target.