Key Health Concerns

Hearing loss is common in people with Noonan Syndrome.

Cardiac abnormalities include pulmonary valve stenosis (a narrowing of the pulmonary valve), and sometimes hypertrophic cardiomyopathy (thickening of the heart muscle). More than 80% of patients with NS have an abnormality of the heart. The most common is an abnormality of the pulmonary valve (which guards the flow of blood out of the right side of the heart to the lung arteries), causing blockage (called pulmonary valve stenosis). Many patients have mild PVS that requires only periodic reevaluation with an echocardiogram (ultrasound study of the heart). If the PVS is or becomes clinically significant, the initial treatment to relieve the blockage is usually with a non-surgical procedure called a heart catheterization. During that, the specialized cardiologist will use a special catheter with a balloon on it to open up the PVS; this is called a pulmonary balloon valvuloplasty. If this fails to relieve the stenosis adequately, which is more frequent in children with Noonan Syndrome, then the patient will typically be referred to a heart surgeon, who will relieve the blockage during open heart surgery. In Noonan syndrome, Isolated holes in the wall between the two collecting chambers (the atria ) are also relatively common; these are called atrial septal defects (ASDs). If they are small, the cardiologist will likely just follow this over time. For moderate or large ASDs, closure will likely be recommended during childhood. This is often done with a different non-surgical procedure during heart catheterization; here, an ASD closure device is inserted through a catheter to close the hole. If the ASD cannot be closed that way, then open heart surgery is needed so the surgeon can close it. There are numerous other types of CHD that have been observed in children with Noonan Syndrome. For all forms of CHD, the management is essentially identical to other children with the same problem who do not have Noonan Syndrome. If a child with Noonan Syndrome will need to undergo open heart surgery, evaluation for bleeding risk is generally undertaken beforehand to help with management during and after the procedure. In addition to CHD, ∼20% of patients with Noonan Syndrome develop a problem in which there is a significant excess of heart muscle, which is called hypertrophic cardiomyopathy (HCM). This is particularly frequent among those with RAF1 and RIT1 changes as the cause of their Noonan Syndrome. HCM presents early in life in Noonan Syndrome, occasionally before birth but usually in the first year or two of life. Severity varies, and the heart thickening can progress over time. In the most severe cases, babies develop heart failure. Treatments for HCM include certain medicines used for HCM generally (these may help with symptoms but are not curative) or heart surgery to remove some of the excess muscle. Recently, a cancer medicine called trametinib has been used for severe HCM in Noonan Syndrome. While a clinical trial has not been performed yet to study this new treatment, the information from the patients treated already seems promising.

Individuals can develop multiple benign bone tumors, most commonly seen in the jaw, known as "giant cell lesions" or "multiple giant cell lesions (MGCL)"

Short stature, growth hormone resistance, delayed puberty and thyroid dysfunction.

Feeding difficulties, failure to thrive, and gastroparesis. Feeding tubes (NG, G-Tube, NJ-Tube)

People with Noonan syndrome may have a tendency to bruise easily or bleed heavily. This can be due to issues with blood clotting. Bleeding problems may not be apparent until a person has surgery or dental work. People with Noonan syndrome often have bleeding symptoms and abnormal lab tests. This can put them at risk for having bleeding complications with surgery, dental procedures, or injuries. It is recommended that you talk to your doctor about these bleeding risks.

A buildup of fluid in the body's tissues. This can cause puffy hands and feet in infants, and can affect the ankles and lower legs in older people.

Low muscle tone. Joint pain, stiffness and hypermobility. Pectus excavatum or pectus carinatum. Scoliosis. Low bone mineral density

Some children may have learning disabilities.

Chiari malformation with obstruction of the CSF. Low-grade gliomas: These are commonly associated with NS. Dysembryoplastic neuroepithelial tumors (DNET): These are commonly associated with NS.

People with Noonan syndrome may have an increased risk of developing leukemia or other cancers, including JMML. Low-grade gliomas: These are commonly associated with NS. Dysembryoplastic neuroepithelial tumors (DNET): These are commonly associated with NS.

External features include: hypertelorism, downward sloping palpebral apertures, epicanthic folds, and ptosis. Increased chances of strabismus, refractive errors, amblyopia, and nystagmus.

Sleep disorders, including obstructive sleep apnea (OSA) and sleepwalking

An atypical kidney structure may increase the risk of urinary tract infections.