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Congenital unilateral or bilateral paralysis of VII and VI nerve  Hypoplasia of  nerve nuclei in the brainstem results in the condition Other cranial nerves like III, IV, V,VIII may also be involved  Exact cause is unknown.  May have - foot abnormalities like club foot  Mental retardation may be present   

Introduction Autosomal Dominant condition  Ras-MAPK pathway Defect  Due to mutation in       PTPN11 protein-tyrosine phosphatase,non-receptor-type 11) gene on chromosome 12.       10–15% are caused by SOS1 (son of seven-less homologue 1 (Drosophila), on      chromosome and RAF1 NS is often associated with advanced paternal age  Karyotype is usually normal. Male: Female - 4:1 Phenotypically looks like Turner So if male and looks like Turner think of Noonan.  Clinical Features  Cardiovascular     Pulmonary valve stenosis (Most common)     Hypertrophic cardiomyopathy      Branch pulmonary artery stenosis     Septal defects  Musculoskeletal      Webbed or short neck      Pectus excavatum or carinatum      Wide-spaced nipples      Wide carrying angle (cubitus valgus)      Short stature in 80% Triangular facies Antimongoloid slant Hypertelorism  Low set ears and posteriorly rotated