A set of 12 PID genes (PRF1, UNC13D, STX11, STXBP2, RAB27A, LYST, AP3B1, SH2D1A, BIRC4, ITK, CD27, and MAGT1) have been established as contributors to the development of cytokine storms, and are dubbed hemophagocytic lymphohistiocytosis (HLH)-related genes [7]. Here, STXBP2 is linked to hemophagocytic syndrome.