Medical Conditions

My Baby Was Diagnosed with Noonan Syndrome

Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist

Content reviewed against published NIH, NORD, Boston Children's guidelines

Last reviewed: May 2026

If your baby has been diagnosed with or you suspect was diagnosed with noonan syndrome, here is what the evidence says.

The short answer

Noonan syndrome is a genetic condition occurring in about 1 in 1,000-2,500 births, caused by mutations in genes of the RAS-MAPK pathway. It affects multiple body systems and is characterized by distinctive facial features, short stature, heart defects (most commonly pulmonary valve stenosis), and varying degrees of developmental delay. While Noonan syndrome is a lifelong condition, the wide range of severity means that many people with Noonan syndrome lead independent, fulfilling lives. Early intervention and comprehensive medical care significantly improve outcomes.

Key takeaways

Noonan syndrome is a genetic condition occurring in about 1 in 1,000-2,500 births, caused by mutations in genes of the RAS-MAPK pathway. It affects multiple body systems and is characterized by distinctive facial features, short stature, heart defects (most commonly pulmonary valve stenosis), and varying degrees of developmental delay. While Noonan syndrome is a lifelong condition, the wide range of severity means that many people with Noonan syndrome lead independent, fulfilling lives. Early intervention and comprehensive medical care significantly improve outcomes.
Usually normal when: Your baby with Noonan syndrome is receiving appropriate cardiac monitoring and developmental support
Call your doctor if: Your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation
Varies by age — see the age-by-age breakdown below

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What Parents Should Know

According to NIH, NORD, Boston Children's guidelines, noonan syndrome is a genetic condition occurring in about 1 in 1,000-2,500 births, caused by mutations in genes of the RAS-MAPK pathway. It affects multiple body systems and is characterized by distinctive facial features, short stature, heart defects (most commonly pulmonary valve stenosis), and varying degrees of developmental delay. While Noonan syndrome is a lifelong condition, the wide range of severity means that many people with Noonan syndrome lead independent, fulfilling lives. Early intervention and comprehensive medical care significantly improve outcomes. At 0-6 months, in infancy, common features include distinctive facial appearance (widely-spaced eyes, low-set ears, deep philtrum), excess nuchal skin or cystic hygroma history, feeding difficulties (poor suck, reflux), and heart defects. A cardiac evaluation (echocardiogram) is one of the first priorities. Feeding challenges are common and may require occupational therapy or specialized nipples. Genetic testing confirms the diagnosis. About 50-80% of cases involve the PTPN11 gene. It is generally considered normal when your baby with Noonan syndrome is receiving appropriate cardiac monitoring and developmental support. However, you should contact your pediatrician promptly if your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal

Worth Discussing

Your baby with Noonan syndrome is receiving appropriate cardiac monitoring and developmental support

Your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation

Your baby is making progress with feeding and developmental milestones, even if at a slower pace

Your baby has unusual or excessive bleeding that does not stop — seek emergency care

Genetic testing has confirmed the diagnosis and you have a care team in place

Your baby has a seizure or sudden change in alertness — call 911

When to Seek Immediate Care

Your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation
Your baby has unusual or excessive bleeding that does not stop — seek emergency care
Your baby has a seizure or sudden change in alertness — call 911

By Age

What to expect by age

0-6 months

In infancy, common features include distinctive facial appearance (widely-spaced eyes, low-set ears, deep philtrum), excess nuchal skin or cystic hygroma history, feeding difficulties (poor suck, reflux), and heart defects. A cardiac evaluation (echocardiogram) is one of the first priorities. Feeding challenges are common and may require occupational therapy or specialized nipples. Genetic testing confirms the diagnosis. About 50-80% of cases involve the PTPN11 gene.

6-12 months

Motor development may be delayed — sitting and crawling often come later than expected. Early intervention services (physical therapy, occupational therapy, feeding therapy) should begin as soon as developmental concerns are identified. Growth is typically below average, and your pediatrician will use Noonan syndrome-specific growth charts. Hearing and vision should be checked, as both can be affected.

1-3 years

Language development may be delayed, and speech therapy is often beneficial. Cognitive ability varies widely — some children are in the normal range, while others have mild to moderate intellectual disability. Behavioral concerns like attention difficulties and social challenges may emerge. Your child's developmental pediatrician can help coordinate therapies. Bleeding tendencies (due to clotting factor deficiencies) should be evaluated before any surgical procedures.

3 years+

With appropriate support, many children with Noonan syndrome thrive in school. Short stature may be addressed with growth hormone therapy, which is FDA-approved for Noonan syndrome. Puberty may be delayed. Ongoing cardiac monitoring is important, as some heart issues can progress or new ones can develop. A multidisciplinary approach — cardiology, endocrinology, genetics, developmental pediatrics — provides the best outcomes.

What to Tell Your Pediatrician

Describe when you first noticed was diagnosed with noonan syndrome and how it has changed over time.
Note your baby's current age and which age-specific patterns you are seeing.
Mention if your baby with Noonan syndrome is having significant feeding difficulties or poor weight gain.
Mention if you notice your baby bruises very easily or bleeds for a long time from minor injuries.
Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...

Your baby with Noonan syndrome is receiving appropriate cardiac monitoring and developmental support
Your baby is making progress with feeding and developmental milestones, even if at a slower pace
Genetic testing has confirmed the diagnosis and you have a care team in place

Mention at your next visit when...

Your baby with Noonan syndrome is having significant feeding difficulties or poor weight gain
You notice your baby bruises very easily or bleeds for a long time from minor injuries
Developmental milestones are significantly delayed beyond what your care team expected
You have concerns about your baby's heart or breathing

Act now when...

Your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation
Your baby has unusual or excessive bleeding that does not stop — seek emergency care
Your baby has a seizure or sudden change in alertness — call 911

What You Can Do at Home

Keep track of when you notice was diagnosed with noonan syndrome — noting the time of day, duration, and any triggers can help your pediatrician.
Remember that your baby with Noonan syndrome is receiving appropriate cardiac monitoring and developmental support — this is generally within the range of normal.
At 0-6 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
While monitoring at home, seek immediate care if your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation.

My Baby Was Diagnosed with 22q11.2 Deletion Syndrome (DiGeorge)

22q11.2 deletion syndrome (also known as DiGeorge syndrome or velocardiofacial syndrome) is caused by a small missing piece of chromosome 22 and is the most common microdeletion syndrome, affecting about 1 in 4,000 births. It can affect many body systems — heart, immune system, palate, calcium regulation, learning, and behavior. The severity varies widely, even within the same family. Some children have significant medical needs, while others have mild features. With appropriate monitoring and support, many people with 22q11.2 deletion syndrome lead fulfilling, independent lives.

My Baby Was Diagnosed with Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS) is an overgrowth disorder affecting approximately 1 in 10,500 births. It is caused by changes in gene regulation on chromosome 11p15. Common features include macrosomia (large body size), macroglossia (large tongue), abdominal wall defects (omphalocele or umbilical hernia), ear creases or pits, and neonatal hypoglycemia. The most important medical consideration is an increased risk of certain childhood cancers (particularly Wilms tumor and hepatoblastoma), which requires regular screening through early childhood. With appropriate monitoring, the prognosis for children with BWS is generally very good.

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Growth Percentile Calculator

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Milestone

Month-by-Month Development

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Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is was diagnosed with noonan syndrome normal?

When should I call the doctor about was diagnosed with noonan syndrome?

Your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation Your baby has unusual or excessive bleeding that does not stop — seek emergency care Your baby has a seizure or sudden change in alertness — call 911

When is was diagnosed with noonan syndrome normal?

Your baby with Noonan syndrome is receiving appropriate cardiac monitoring and developmental support Your baby is making progress with feeding and developmental milestones, even if at a slower pace Genetic testing has confirmed the diagnosis and you have a care team in place

What causes was diagnosed with noonan syndrome?

What should I mention to my pediatrician about was diagnosed with noonan syndrome?

You should mention was diagnosed with noonan syndrome at your next visit if: Your baby with Noonan syndrome is having significant feeding difficulties or poor weight gain. You notice your baby bruises very easily or bleeds for a long time from minor injuries. Developmental milestones are significantly delayed beyond what your care team expected.

Is was diagnosed with noonan syndrome normal at 0-6 months?

Is was diagnosed with noonan syndrome normal at 6-12 months?

Should I go to the ER for was diagnosed with noonan syndrome?

Seek emergency care if your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation, or if your baby has unusual or excessive bleeding that does not stop — seek emergency care. When in doubt, call your pediatrician's after-hours line for guidance.

Does was diagnosed with noonan syndrome go away on its own?

In many cases, was diagnosed with noonan syndrome resolves on its own, especially when your baby with Noonan syndrome is receiving appropriate cardiac monitoring and developmental support. By 3 years+, with appropriate support, many children with Noonan syndrome thrive in school. Short stature may be addressed with growth hormone therapy, which is FDA-approved for Noonan syndrome. Puberty may be delayed. Ongoing cardiac monitoring is important, as some heart issues can progress or new ones can develop. A multidisciplinary approach — cardiology, endocrinology, genetics, developmental pediatrics — provides the best outcomes.

NIH NORD BOSTON CHILDREN'S

References

[1]MedlinePlus. Noonan Syndrome. NIH
[2]National Organization for Rare Disorders. Noonan Syndrome. NORD
[3]Boston Children's Hospital. Noonan Syndrome. Boston Children's

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss My Baby Was Diagnosed with Noonan Syndrome.

Things to mention

Describe when you first noticed was diagnosed with noonan syndrome and how it has changed over time.
Note your baby's current age and which age-specific patterns you are seeing.
Mention if your baby with Noonan syndrome is having significant feeding difficulties or poor weight gain.
Mention if you notice your baby bruises very easily or bleeds for a long time from minor injuries.
Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

Your baby with Noonan syndrome is having significant feeding difficulties or poor weight gain
You notice your baby bruises very easily or bleeds for a long time from minor injuries
Developmental milestones are significantly delayed beyond what your care team expected

Urgent signs to report immediately

Your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation
Your baby has unusual or excessive bleeding that does not stop — seek emergency care
Your baby has a seizure or sudden change in alertness — call 911

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

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Bottom line

Most cases of was diagnosed with noonan syndrome are normal. Talk to your pediatrician if your baby has difficulty breathing, turns blue, or seems to tire excessively during feeds — this may indicate a cardiac issue requiring urgent evaluation.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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