Noonan syndrome

Noonan syndrome

Noonan’s syndrome is a group of disorders present in a child since birth. It is a genetic disorder that usually runs in the family. It has several unique features and is associated with various congenital anomalies. Noonan syndrome is a hereditary condition that hinders proper growth in several body regions.

The symptoms of Noonan syndrome can manifest in several ways, like unusual facial features, small height, heart disorders, various physical issues, and developmental disabilities.

Associated Anatomy: Head, skin, lungs, heart

Noonan syndrome Causes

Although the exact cause of Noonan syndrome is unknown, it was associated with a particular mutation in one or more specific genes (PTPN11, SOS1, RAF1, RIT1, etc.). These mutations or genetic changes can happen due to two primary reasons:

  1. Inherited Mutation: In almost 50 % of the cases, it was observed that these mutations are inherited from the parents.
  2. Random Mutation: These mutations are not linked to any genetic predisposition but can occur randomly without any known cause.

Noonan Syndrome Symptoms

Noonan syndrome can cause a wide range of symptoms depending on the individual. The severity of symptoms depends on the responsible gene, ranging from mild to severe. The following signs and symptoms are based on the affected body structures seen in patients with this disorder.

Head and neck

  • An oversized head large head with a deep groove in the centre of the top lip, a tiny jaw, misaligned teeth, and backward-pointing ears
  • Eyes that are bluish-green or blue and have extremely thick or sagging eyelids (ptosis)
  • Neck webbing and a low hairline at the back of the neck


  • Hypertrophic cardiomyopathy - thickening of the heart muscle
  • Pulmonary stenosis - an obstruction of blood flow from the heart to the lungs
  • Atrial septal defect - an opening between the upper heart chambers


  • Protruding toes and finger pads
  • Malformed or discoloured nails
  • Hair texture changes

Other common signs and symptoms

  • Lymphedema - swollen extremities caused due to retention of fluid
  • Feeding difficulties and inability to grow or gain weight in infants
  • Small stature
  • Abnormal spine curvature (Scoliosis)
  • Infertility and delayed puberty
  • Mental abnormalities
  • Hearing loss or vision abnormalities
  • Bleeding issues

Noonan syndrome Treatment

There is no cure for Noonan syndrome at the moment. However, The goal of treatment and management is to relieve some of the problems that come with it. If your kid has been diagnosed with Noonan syndrome, they may get the following treatment:

  • It may be enough to closely monitor your child for a small cardiac abnormality on an outpatient basis.
  • Surgical repair of any serious structural abnormalities in the heart
  • Your infant may be fed through a nasogastric tube if feeding is a challenge
  • To cure short-sightedness, you'll need prescription glasses.
  • Frequent growth hormone injections – to assist your child reach a height more in line with their age, surgical repair of undescended testicles (orchidopexy).
  • Anticonvulsant therapy – If your kid has seizures, speech therapy and special schooling are required for around 10% of children with Noonan syndrome.
  • If effective therapy for moderate blood clotting disorders is not available, behavior modification may be used.
  • Orthodontic and dental treatment

Typical Test

The initial Noonan syndrome diagnosis is made with the help of your medical history, signs, symptoms, and physical examination. Family history is also essential, which helps understand the risk of genetic predisposition. Once the initial diagnosis is established, your doctor may advise additional molecular genetic tests to confirm the diagnosis. The sooner the Noonan syndrome is detected, the sooner treatment and preventative methods may be initiated, resulting in better patient outcomes.

Primary Prevention

There is no way to prevent getting Noonan syndrome. Noonan syndrome is caused by genetic mutations inherited from parents or developing spontaneously.

Alternate Name

A Noonan syndrome is also known as Male Turner Syndrome, Noonan-Ehmke syndrome, or Ullrich-Noonan syndrome.


NS affects roughly 1 in 1000 persons, and about 1 in 2,000 people have a more severe version of the disease. Males appear to be more susceptible than females.

Expected Prognosis

Patients suffering from Noonan's syndrome may present a broad range of prognoses. It may range from prenatal death to normal life with many symptoms or difficulties. Fortunately, despite developmental delays, most individuals will eventually be able to function properly as adults. Most persons with Noonan syndrome live healthy lives after receiving therapy. According to the findings, a diagnosis of hypertrophic cardiomyopathy before the age of two is linked to the greatest risk of cardiac mortality. Early diagnosis and treatment are critical for treating symptoms and avoiding complications.

Possible Complication

When left untreated, Noonan syndrome may lead to mental difficulties and communication and behavioral challenges. Cancers such as leukemia are another complication commonly seen in persons with Noonan syndrome in the later stages of life. Other complications that can be seen in addition to these are:

  • Developmental delays: Children with Noonan syndrome may require a specific plan to address their educational and developmental requirements if they have substantial learning problems, mental impairments, or other developmental problems.
  • Bleeding problems: Abnormally heavy bleeding is common, although it isn't always noticed until dental work or surgery is done. It's critical to be informed of this danger before undergoing any operations.
  • Excess fluid build-up: Due to lymphatic problems, excess fluid can collect around the lung and heart, presenting a threat.

Our BLK-Max Medical Experts

If you are facing any similar signs or symptoms please contact the BLK-Max team to schedule an appointment at : +91-11-30403040

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