SCN4B and Global developmental delay: We found 13 DEX VGICs including the sodium channels Scn1a, Scn4b and Scn8a, the potassium channels Kcnh1, Kcnq5, Kcnj6, Kcna5, Kcnv1, Kcnk4 and Kcnma1, and the calcium channels Cacna1c and Cacna2d2 (Fig. 6c), many of which are associated with neuropsychiatric syndromes (Scn1a in Dravet syndrome, Cacna1c in Timothy syndrome, Kcnma1 in developmental delay and epilepsy, Scn8a in early epileptic encephalopathy and cognitive impairment, Kcnh1 in Temple-Baraitser syndrome; blue in Fig. 6c).