Diagnosis of NS is established genetically by finding pathogenic variant in any of the following genes: PTPN11, SOS1, SOS2, RAF1, KRAS, NRAS, MRAS, MAP2K1, BRAF, RASA2, LZTR1, RRAS and RIT1. Noonan syndrome with multiple lentigines (NSML or LEOPARD syndrome), must also be included in the differential diagnosis. This evidence concerns the gene NRAS and Noonan syndrome with multiple lentigines.