Hence, many of the genetic etiologies identified in the cohort which currently could not be classified into electroclinical syndromes, such as affected individuals with KCNT1, CACNA1A, PUM1, FGF12, AP3B2, PRRT2, GRIN2A, and Angelman syndrome may be classified as etiology-specific syndromes in the future. This evidence concerns the gene AP3B2 and Angelman syndrome.