Familial hemophagocytic lymphohistiocytosis type 5 is due to mutations in STXBP2 (also named MUNC18-2; OMIM 601717) (40, 41) and has been reported to account for up to 20% of cases with FHL in the German series (42). The gene discussed is STXBP2; the disease is hemophagocytic syndrome.