UNC13D and immune system disorder: These include familial haemophagocytic lymphohistiocytosis, an immune disorder caused by mutations in protein unc-13 homologue D (MUNC-13-4; also known as UNC13D) (Feldmann et al., 2003), syntaxin 11 (zur Stadt et al., 2005) or syntaxin binding protein 2 (zur Stadt et al., 2009).