RASopathies [26 genes]

• Subjects under suspicion or clinical diagnosis of Noonan, LEOPARD, Costello, Legius or cardiofaciocutaneous syndrome. There is frequent clinical overlapping among these syndromes (these patients share a variable degree of intellectual disability, cardiac anomalies, facial dysmorphism, skin anomalies, and predisposition to develop cancer); therefore the genetic study would facilitate differential diagnosis. All these syndromes share an autosomal dominant pattern of inheritance.
• Familial study: A search for the mutation previously identified in a proband (relatives of patients with Noonan, LEOPARD, Costello, Legius or cardiofaciocutaneous syndrome, in which a mutation has been previously identified).

The probability of identifying a causal mutation when a patient has been diagnosed with one of these syndromes is high, over 70% in all cases. It can range from 70%-80% for one mutation or relevant variant in case of Noonan syndrome to 88%-98% in the case of Legius syndrome.