Recently, patients with deficiency in IFNAR1, IFNAR2, STAT1, and STAT2 genes developing HLH have been described (Duncan et al., 2015; Burns et al., 2016; Hoyos-Bachiloglu et al., 2017; Alosaimi et al., 2019; Boehmer et al., 2020). The gene discussed is IFNAR2; the disease is hemophagocytic syndrome.