MRGPRX4 and diabetes mellitus: Interestingly, the nateglinide, a FDA approved drug for the treatment of diabetes, previously reported as MRGPRX4 agonist and has itch side effect (Kroeze et al., 2015; Kozlitina et al., 2019), (Figure 3—figure supplement 1f) —but not vehicle—induced a robust itch sensation in healthy subjects (Figure 6a1, a2).