Noonan syndrome

Noonan syndrome is a rare genetic disorder. If you have it, you may have certain recognizable facial features, short stature, and an unusual chest shape. You may also have heart defects.

This can cause a wide range of other physical and developmental symptoms that usually start at birth.

There is no cure, but doctors can treat some symptoms as they occur.

What are the reasons?

Noonan syndrome is caused by a genetic abnormality. Scientists have identified four genes involved in the syndrome: PTPN11, SOS1, RAF1 and KRAS.

This syndrome can be contracted in two ways:

A genetic mutation is passed on to you from your parents
The altered gene first occurs while you are still in the womb.

What are the symptoms?

Symptoms are numerous and may be mild, moderate, or severe.

Head, face, and mouth

Widely spaced eyes
Deep groove between the nose and mouth
Low-set ears that arch backward
Short neck
Extra skin on the neck (“webbing”)
Small lower jaw
High arch in the roof of the mouth
Crooked teeth

Bones and chest

Short height (about 70% of patients)
Either sunken or protruding chest
Low-set nipples
Scoliosis

Heart

Most babies with Noonan syndrome are also born with heart disease. They may have:

Narrowing of the valve that moves blood from the heart to the lungs
Swelling and weakening of the heart muscle
Atrial septal defects

Blood

Excessive bruising
Nosebleeds
Prolonged bleeding after an injury or surgery
Blood cancer (leukemia)

Puberty

Delayed puberty
Testes that don’t descend -- this can cause infertility

Other Symptoms

Vision or hearing problems
Feeding problems (these usually improve by age 1 or 2)
Mild intellectual or development disability (although most have normal intelligence)
Puffy feet and hands (in infants)

How is it diagnosed?

Before your baby is born, your doctor may suspect Noonan syndrome if a pregnancy ultrasound shows:

Extra amniotic fluid around your baby in the amniotic sac
A cluster of cysts in your baby’s neck
Problems with the structure of the heart or other structural problems

Your doctor may also suspect Noonan syndrome if you have abnormal results from a specialized prenatal test called a triple maternal serum screen.

Most of the time, he will know that your baby has the condition at birth or shortly after he is seen. But sometimes it is difficult to recognize and diagnose.

What is the treatment?

Your doctor will prescribe treatment for your child's symptoms or complications. For example, growth hormones can help with growth problems.

What else should I know?

If you have Noonan syndrome, you may be wondering if your future children will have it. It depends on your family history

If one of your parents has the disease, they have a 50% chance of passing it on to you.

But if you have Noonan syndrome and no one in your family has it, you may have inherited the defective gene. Doctors call this a "de novo mutation." In this case, your chances of passing it on to an unborn child are very low - less than 1%.

If you are concerned, consult with a geneticist. They can run tests to look for mutations that occur with this syndrome and help confirm if your child has it.