• Delayed puberty
• Down-slanting or wide-set eyes
• Hearing loss (varies)
• Low-set or abnormally shaped ears
• Mild mental retardation (only in about 25% of cases)
• Sagging eyelids (ptosis)
• Short stature
• Small penis
• Undescended testicles
• Unusual chest shape (usually a sunken chest called pectus excavatum)
• Webbed and short-appearing neck

Examination may show an extra fold of skin above the eyes near the nose (epicanthal folds) and arms that may be held at an unusual angle.

There may be signs of congenital heart disease (especially pulmonary stenosis, occasionally ASD).

Blood tests to look at platelet count and blood factors may reveal signs of a bleeding tendency.

Specific tests depend on what the symptoms are. For example, if there are signs of heart disease, an EKG, chest x-ray, or echocardiogram may be recommended. Hearing tests are recommended for those who have signs of decreased hearing.

Genetic testing can identify the mutations in the four genes which cause Noonan syndrome.