. LEOPARD syndrome 2 (LS-2) (OMIM #611554) is a rare, dominantly inherited genetic disorder affecting multiple organ systems. We report two unrelated females of different ages whose phenotype fits best in the category of LEOPARD syndrome, both with proven mutations in the RAF1 gene not previouslyreported in pediatric patients. In our 10-year-old patient, who was negative in the PTPN11 gene analysis but involving the RAF1 gene in a complementary analysis, the sequence variant Ser257Leu (770C > T, exon 7) was detected, which previously had been reported in only one 35-year-old woman with LS. The second patient was a two-year-old female infant with Ser259Leu mutation in the same gene, described in several patients with Noonan syndrome (NS) but not in LS patients of any age. The first girl had ventricular and supraventricular extrasystoles, and the second had episodes of paroxysmal supraventricular tachycardia. Echocardiographic examination revealed biventricular obstructive hypertrophic cardiomyopathy in both patients.