GNAO1 and Epileptic encephalopathy: GNAO1 mutations have been associated with two phenotypes: a severe, early‐infantile epileptic encephalopathy with burst‐suppression (EIEE17, OMIM 6154731) and a neurodevelopmental disorder with involuntary movements (NEDIM, OMIM 6174932, 3, 4), with or without seizures.