Table 1.

Clinical Features of RASopathies

Syndrome	Non-Neoplastic Features	Neoplastic Features
Legius Syndrome/NF1-Like Syndrome	Multiple café-au-lait macules; macrocephaly; skin fold freckling; learning disability; Noonan syndrome-like facies; cardiac valvular abnormalities	Lipomas
Noonan Syndrome	Macrocephaly; distinctive facies; short stature; mild cognitive impairment; webbed neck; pectus excavatum; cryptorchidism	Juvenile myelomonocytic leukemia-like myeloproliferative disorders
LEOPARD Syndrome/ Noonan Syndrome with Multiple Lentigines	Multiple lentigines; electrocardiographic conduction abnormalities; ocular hypertelorism; pulmonary stenosis; abnormal genitalia; retardation of growth; sensorineural deafness	None
Noonan-Like Syndrome	Noonan syndrome-like facies; hyperpigmented skin lesions; microcephaly; cardiomyopathy; arrthymias; valvular abnormalities; developmental delays	None
Noonan-Like Syndrome with Loose Anagen Hair	Cardiovascular abnormalities; macrocephaly; short stature; mild cognitive impairment; fine sparse and easily pluckable hair	None
Costello syndrome	Cardiovascular abnormalities; coarse facies with facial warts; short stature; failure to thrive; severe feeding difficulties; curly hair; palmar keratosis. Variant exists presenting with a congenital myopathy with excess of muscle spindles.	Increased risk of malignant tumors including transitional cell carcinomas of bladder, rhabdomyosarcomas and ganglioneuroblastomas
Cardiofaciocutaneous (CFC) Syndrome	Cardiovascular abnormalities; distinct facies; failure to thrive; nevi, lentigines, palmar-plantar keratosis; curly hair; seizures; severe intellectual disability	None
Hereditary Gingival Fibromatosis	None	Gingival fibromatosis
Capillary Malformation-Arteriovenous Malformation Syndrome	Capillary malformations; arteriovenous malformations	None