The physiologic implications of these proteolytic cleavages remain unclear, though increased soluble TREM2 has been reported in the CSF of early‐stage Alzheimer's disease (Suarez‐Calvet et al, 2016), and study of a variant p.H157Y reported to be associated with AD in the Han Chinese population has been shown to increase ectodomain shedding (Jiang et al, 2016a; Schlepckow et al, 2017; Thornton et al, 2017). Here, TREM2 is linked to early-onset autosomal dominant Alzheimer disease.