Which are the symptoms of Noonan Syndrome?

Symptoms of Noonan Syndrome

Noonan syndrome is a genetic disorder that affects various parts of the body, causing a wide range of symptoms. It is characterized by distinctive facial features, developmental delays, and potential heart defects. While the severity and specific symptoms can vary among individuals, there are several key signs that may indicate the presence of Noonan syndrome.

Facial Features:

One of the most noticeable characteristics of Noonan syndrome is the distinct facial appearance. Individuals with this condition often have a triangular-shaped face with a high forehead, drooping eyelids (ptosis), wide-set eyes (hypertelorism), and low-set ears. The neck may also appear webbed or have excess skin folds.

Growth and Development:

Noonan syndrome can affect growth and development in various ways. Short stature is a common characteristic, with affected individuals typically being shorter than their peers. Delayed growth and puberty may also be observed. Additionally, developmental delays can affect motor skills, speech, and cognitive abilities. Some individuals may have learning disabilities or intellectual impairment.

Cardiac Abnormalities:

Heart problems are a significant feature of Noonan syndrome, with approximately 80% of affected individuals experiencing some form of congenital heart defect. These defects can range from mild to severe and may include pulmonary valve stenosis, hypertrophic cardiomyopathy, atrial septal defects, or ventricular septal defects. Regular cardiac evaluations are crucial for individuals with Noonan syndrome.

Characteristic Skin and Body Features:

Several distinctive skin and body features are associated with Noonan syndrome. These include increased skin pigmentation (café-au-lait spots), curved spine (scoliosis), chest deformities (pectus excavatum or pectus carinatum), and lymphedema (swelling due to fluid retention). Some individuals may also have low muscle tone (hypotonia) or joint abnormalities.

Other Possible Symptoms:

While the following symptoms are not always present, they can occur in individuals with Noonan syndrome:

• Intellectual disability: Some individuals may have mild to moderate intellectual disability.


• Bleeding disorders: A tendency to bruise easily or experience abnormal bleeding may be observed.


• Gastrointestinal issues: Problems such as chronic diarrhea, feeding difficulties, or gastroesophageal reflux disease (GERD) may occur.


• Hearing loss: Some individuals may have hearing impairment or require hearing aids.


• Eye abnormalities: Vision problems, such as nearsightedness (myopia) or crossed eyes (strabismus), can be present.


• Genital abnormalities: Males may have undescended testicles (cryptorchidism) or other genital abnormalities.

Noonan syndrome is a complex condition, and the combination and severity of symptoms can vary widely. It is important to note that not all individuals with Noonan syndrome will exhibit all of these symptoms, and some may have additional features not listed here. A thorough evaluation by a healthcare professional experienced in genetic disorders is necessary for an accurate diagnosis.