Noonan syndrome: symptoms and treatment

Noonan syndrome is a congenital genetic disorder. If someone is born with this condition, there are a multitude of abnormalities that doctors must focus on, such as disorders of the heart, pulmonary artery and facial deformities. What is Noonan Syndrome, what are the most common features and what is the treatment?

Noonan’s syndrome

  • Noonan’s syndrome
  • Lung and heart abnormalities
  • Facial abnormalities
  • How often does it happen?
  • Therapy


Noonan’s syndrome

Noonan syndrome is a congenital genetic disorder that occurs in both men and women. This name used to be used when talking about the male form of Turner syndrome, which only occurs in women, but it is now known that these are two very different genetic abnormalities. The syndrome also has many similarities with Costello syndrome. The most common consequences are heart defect, short stature, learning difficulties, chest indentation, poor blood clotting, undescended testicles and facial deformities. The syndrome is named after American cardiologist and discoverer of the condition Dr. Jacqueline Noonan.

Other names

The syndrome is also known by the following names:

  • Noonan syndrome
  • Familial Turner syndrome
  • Male Turner Syndrome
  • Noonan-Ehmke syndrome
  • Pseudo-Ullrich-Turner syndrome
  • Ullrich-Noonan syndrome


Lung and heart abnormalities

The following lung and heart abnormalities are common in Noonan syndrome:

  • Pulmonary valve stenosis (narrowing of the pulmonary artery at the level of the valves)
  • Hypertrophic cardiomyopathy (thickening of the heart muscle, poorly functioning muscle tissue)
  • Atrial septal defect (opening in the atrial septum)
  • Ventricular septal defect (opening in the ventricular septum)


Facial abnormalities

The following abnormalities of the face and neck are common in Noonan syndrome:

  • Hypertelorism (eyes set too far apart)
  • Big eyes
  • Ptosis (drooping of the eyelids)
  • Flat nose bridge
  • Abnormal position and shape of the ears
  • Webbed neck (folds in the skin of the neck)
  • Low hairline
  • Abnormal amount of freckles


How often does it happen?

About 1 in 1,000 to 2,500 children are born with this syndrome. It is one of the most common genetic syndromes in which a heart defect is a hallmark, with a similar risk as in people with Down syndrome. It is true that the severity of the situation can vary enormously among people with Noonan syndrome. For this reason, with a less serious abnormality it can sometimes happen that the syndrome is only diagnosed by a doctor after years.
Noonan syndrome is autosomal dominant. There may also be a rare autosomal recessive hereditary form, but more research is needed.


Each individual case is treated differently. A congenital heart deformity can be corrected surgically. The scrotum can be surgically updated. Sometimes growth hormones are prescribed to help someone grow a little taller. A common treatment for children with Noonan syndrome is balloon dilation, in which a small balloon is inflated in an artery to remove narrowing or blockages. Learning disabilities can be accommodated in special education. Due to the diversity of symptoms and their severity, there is no single fixed treatment method and a patient will often remain under treatment by multiple specialists throughout their life.

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