Noonan Syndrome-Symptoms, Causes, Treatment

Noonan Syndrome is a genetic disorder that can equally affect men and women. It prevents the normal development of the various parts of the body such as the heart, brain and all other parts including facial or body features. This type of syndrome cannot be easily identified even from the early stages of birth, which is why this is often referred to as a “hidden condition”.

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Characteristics of a Person with Noonan Syndrome

To better understand Noonan Syndrome and its principal symptoms, here is a list of defects or abnormalities an individual suffering from this condition can manifest.

• Heart problems– two thirds of the patients might show signs of heart defects such as Pulmonary Valvular Stenosis, Septal Defects (atrial or ventricular), Heart Murmur, and Cardiomyopathy.

• Gastrointestinal problems – failure to thrive (during infancy), digestive problems, decreased appetite, frequent or at times forceful vomiting, and swallowing difficulties.

• Cryptorchidism – this is a condition when one or both testes of the male scrotum are missing.

• Lymphatic problems – webbed neck or posterior cervical hygroma and lymphedema or the buildup of body fluids.

• Developmental problems – poor coordination, learning disabilities, clumsiness, motor delay, speech or language delays, and mental retardation which rarely happens.

• Joint pains with unidentified causes.

• Hematologic problems – bruised easily, low platelet count, Von Willebrand Disease, blood clot disorders, and partial deficiency on Factor VIII:C, Factor XI:C, and Factor XII:C.

Abnormalities that are visible through the physical appearance of the patient include:

• Short Stature / Growth retardation

• Scoliosis

• Dwarfism

• Joint contractures

• Short neck or webbed neck

• Curly hair

• Triangular facial features

• Large head

• Broad forehead

• Wide set of eyes / Bulging eyes

• Drooping eyelids

• Nystagmus (involuntary eye movements)

• Small nose or upturned nose

• Low set of ears

• Ears are set on a backward rotated appearance

• Thick outer rim (helix in the ear)

• Deep groove philtrum

• Micrognathism or undersized jaw

• Dental problems

• Tongue control difficulties

• Blunt fingers

• Elbow deformity

• Keloid

• Pigmented nevi

• Hyperkeratosis

• Lymphedema

Signs of Noonan Syndrome

As said earlier, Noonan Syndrome cannot be detected easily and features may change as the child gets older. But with regards to the characteristics as stated above, signs to watch out for especially in young infants are a wide set of eyes and ears, short neck, and low hairline most specifically at the back of the head. When you suspect your child to have inherited this type of condition, consult with the doctor right away so that proper actions can be taken to avoid further complications.

Causes of Noonan Syndrome

Noonan Syndrome is a congenital disease that is believed to be similar to Turner’s syndrome. However, they have distinct causes. Though both are genetically acquired, with Noonan Syndrome, there is still a possibility that a person with no family history can still develop the syndrome.

Scientists believed that a mutation on a particular gene is the main reason for developing such disorder. This mutation can be a result of a defective gene inherited from a parent, or it may have resulted from spontaneous mutation in children who have no genetic predisposition for the condition.

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There are seven known genes that can bring about Noonan Syndrome. However, there are cases of Noonan Syndrome that do not show any signs of mutation on either one of the seven genes. This means there may still be other genes that cause the disease which are not known to us just yet.

Complications of Noonan Syndrome

Because it’s hard to detect Noonan Syndrome, a possibility of complications may arise depending on the condition’s severity. These complications include:

• Developmental issues – a child with severe developmental problems may have difficulties in spatial sense and organization. Children may require special attention on their learning or education.

• Bleeding or bruising – excessive bleeding or bruising problems can create greater problems especially during surgery and dental works. Children with this syndrome are also advised to stay away from aspirin or any products with aspirin for it can thin the blood.

• Lympathic complications – fluids collected in the lungs and heart cavity should be drained out or it may lead to infection or weight loss.

• Genital complications – an abnormal kidney structure may increase the rate of urinary tract infections in women; while men may develop fertility problems such as low sperm count and other fertility issues due to undescended testicles.

• Low self esteem and social difficulties because of their physical abnormalities or deformities.

• Heart structure problems

• Short stature

Tests and Diagnosis

A person with family history of Noonan Syndrome may require genetic testing to identify if any of the genes may have mutated. If yes, blood tests, x-rays, hearing test and other medical evaluations would be advisable to detect which of the organs are directly affected.

While for those with no family history, detection might not be possible until adulthood when physical abnormalities are already visible. Patients with suspected Noonan Syndrome will need to undergo either an Electrocardiogram (ECG) or Echocardiogram tests to identify heart problems for which almost 90% may be affected.

Treatment  for Noonan Syndrome

Direct treatment is still not possible as of the moment; rather, treatments are directed towards the symptoms and complications that arise from the condition. To address the problems associated with Noonan Syndrome, certain drugs can be given for heart problems, growth supplements or growth hormone therapy, and drugs for blood clotting among others. In some cases, the patient may need surgery.

It is also important that the family should also participate in genetic counseling. The one suffering from the condition need not fight it alone; support and love from family would be of great help.

Noonan Syndrome Life Expectancy

Life expectancy in case of Noonan syndrome depends on how well the person is taken care of, the complications of the syndrome etc. But it has been observed that the average life expectancy of a person with Noonan syndrome is ten years lesser than what it would have been for a normal person without the disease.


Couples with history of Noonan Syndrome should consider getting genetic counseling prior to building a family. However, this disease can also occur spontaneously even if there is no family history of the disorder. Therefore, there is no way it can be prevented, but early detection is essential to avoid possible complications so that a Noonan Syndrome patient can still live a normal and happy life.

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