STXBP2 and neurodevelopmental disorder: While Munc18‐1 is associated with infantile encephalopathy with epilepsy and other neurodevelopmental disorders (Stamberger et al, 2016; Abramov et al, 2020), Munc18‐2 is expressed in lymphocytes and other cells of the hematopoietic system, as well as epithelial cells, and mutations cause familial hemophagocytic lymphohistiocytosis type 5 (Cote et al, 2009).