Heterozygous de novo mutations in the neuronal protein Munc18‐1 (also known as STXBP1) were originally described in 2008 in five patients with Ohtahara syndrome, a severe infantile epileptic encephalopathy (Saitsu et al, 2008), and have since been linked to a series of neurodevelopmental disorders (Stamberger et al, 2016). Here, STXBP1 is linked to neurodevelopmental disorder.