XIAP and hemophagocytic syndrome: According to the Histiocyte Society classification of histiocytic disorders, primary HLH is associated with several Mendelian inherited immune disorders, including defects in lymphocyte cytotoxicity (FHL, XLP1), pigmentation disorders, such as Griscelli syndrome 2, Chédiak–Higashi syndrome, and Hermansky–Pudlak syndrome type II, as well as HLH related to abnormalities of inflammasome activation: XLP2, NLRC4, and CDC42 changes (Emile et al. 2016; Lam et al. 2019).