MAP2K2 and Costello syndrome: The remaining genes involved were RAF1 (three patients, all with Costello syndrome suspicion), RIT1 (two patients), BRAF (one patient), MAP2K1 (three patients), MAP2K2 (two patients), PTPN11 (two patients), SOS1 (one patient), and SHOC2 (three patients, two of them with Costello syndrome suspicion).