The symptoms of Noonan syndrome can be mild to severe. Two children with Noonan
syndrome may have completely different symptoms and skills.
What Causes Noonan Syndrome?
A gene mutation
(change) causes Noonan syndrome. Many different gene mutations can cause it.
Who Gets Noonan Syndrome?
Everyone has two copies of almost every gene. It only takes one changed gene to
cause Noonan syndrome. Children of a parent who has Noonan syndrome have a 50% chance
of having it too.
How Is Noonan Syndrome Diagnosed?
Doctors usually notice the features of Noonan syndrome at birth or soon afterward
and suspect the diagnosis. The doctor will:
ask about the family history of genetic conditions
do an exam
consider other genetic disorders with similar symptoms
Based on the results of these steps, the doctor will decide if a child may have
A geneticist (a doctor who specializes in genetic disorders) will
order a genetic test
to see which mutation the child has. Knowing which gene changed can help doctors get
a better idea about which symptoms will be most challenging for the child.
understand their chances of having another child with Noonan syndrome
What Problems Can Happen?
As they grow into adulthood, most children with Noonan syndrome have:
a final adult height near the lower end of the average range
heart problems that may get worse, so they need to see a heart specialist regularly
a slightly higher risk of getting leukemia
a life expectancy that usually depends on how well their heart is working
A child with Noonan syndrome who does not have serious heart problems usually:
does very well with support
and the teenage growth spurt later than most peers
The medical challenges of Noonan syndrome can be stressful for your child and you.
But you're not alone. The care team will work together to help manage problems, and
to support your family. You can also ask about support groups, or visit online sites
such as The Noonan Syndrome Foundation.