Developmental and Epileptic Encephalopathy 15, also known as epileptic encephalopathy, early infantile, 15, is related to salt and pepper syndrome and thiamine-responsive megaloblastic anemia syndrome. An important gene associated with Developmental and Epileptic Encephalopathy 15 is ST3GAL3 (ST3 Beta-Galactoside Alpha-2,3-Sialyltransferase 3), and among its related pathways/superpathways are Metabolism of proteins and Transport to the Golgi and subsequent modification. Affiliated tissues include eye, and related phenotypes are hypotonia and irritability