TLR4 and Alzheimer disease: Cellular and animal studies targeting PLCG2 variants have revealed their impact on microglia under AD conditions, including the association of PLCγ2 with two pathological markers of AD, Aβ and p-tau, and the relationship with many AD-related effectors such as TREM2, TLR4, and others (Shen et al., 2008; Matarin et al., 2015; Sierksma et al., 2020; Tsai et al., 2022).