Keywords: AS, Angelman syndrome; DS, Down syndrome; UBE3A, E3 ubiquitin–protein ligase; PWS, Prader–Willi syndrome; NS, Noonan syndrome; RAS–MAPK, Ras/mitogen activated protein kinase; PTPN11, Protein Tyrosine Phosphatase, Non-receptor type 11; SOS1, Son of Sevenle