The clinical phenotypes related to C-terminal variants are characterized by severe neonatal-onset dyshematopoiesis and immune dysregulation including autoinflammation, rash, and HLH (NOCARH syndrome) (Gernez et al., 2019; Lam et al., 2019; He et al., 2020; Coppola et al., 2022) with a chronic excess of the inflammatory cytokine, IL-18 as a hallmark of these disorders (Miyazawa and Wada, 2022; Shimizu et al., 2022). Here, IL18 is linked to hemophagocytic syndrome.