In addition, patients with mutations inSTXBP2, encoding the syntaxin-binding protein-2 (MUNC18-2) protein, also have intestine-related hallmarks of MVID besides their primary diagnosis of familial hemophagocytic lymphohistiocytosis type 5 (FHL5), a hyper-inflammatory immune disorder14. Here, STXBP2 is linked to microvillus inclusion disease.