Rare congenital disorder with multiple anomalies including: characteristic dysmorphic craniofacial features, musculoskeletal abnormalities, neurocognitive delay, and high prevalence of cancer. Germline mutations in H-Ras protein can cause costello syndrome. costello syndrome shows early phenotypic overlap with other disorders that involve map kinase signaling system (e.g., noonan syndrome and cardiofaciocutaneous syndrome).