Second, mutations that perturb STING trafficking alone (in the absence of a ligand) can activate STING signaling, such as gain-of-function mutations seen in STING-associated vasculopathy with onset in infancy (SAVI), loss-of-function mutations seen in COPA syndrome, GCC2 deficiency, AP-1 deficiency, ESCRT deficiency, and NPC1 deficiency (Chu et al., 2021; Lepelley et al., 2020; Tu et al., 2022; Liu et al., 2014; Gentili et al., 2022Preprint; Liu et al., 2022b). This evidence concerns the gene STING1 and STING-associated vasculopathy with onset in infancy.