NAV1 and neurodevelopmental disorder: We identified de novo variants absent in population databases in NPY2R, MYO1D, UNC50, SPICE1, NAV1, and LRIF1. None of these genetic etiologies are established in neurodevelopmental disorders or epilepsy, but occur in brain‐expressed genes intolerant to mutation, including genes implicated in brain development (NPY2R, UNC50, NAV1,Supplementary Information).