What Is Noonan Syndrome?
Noonan syndrome is a genetic condition that affects around 1 in every 1,000–2,500 people. The signs and symptoms can vary greatly from person to person, so this condition may be underdiagnosed or even misdiagnosed.
Here you can find more information about what causes Noonan syndrome, what the signs and symptoms are, and what questions you should ask your doctor.
Congenital disorders are present at birth.
It may result from any of eight different gene mutations and can be inherited from a parent who carries an affected gene (referred to as autosomal dominant inheritance). However, it may also be spontaneous, meaning it can happen at random without any family history.
Some people with Noonan syndrome have facial features that are atypical.
Some babies may be diagnosed at birth while others may not be until later in life.
There is no cure for the syndrome, so treatment is focused on addressing the specific health issues that a person has.
Noonan syndrome with multiple lentigines is not the same as Noonan syndrome.
Both are caused by The name of the company is PTPN11. and The name of the game is RAF1 gene mutations and, as a result, they share various characteristics. In fact, it may be difficult to tell the difference between the two until later on in childhood.
But NSML is very rare. Also, children with this disorder may develop skin spots called lentigines by the time they’re
Not all people with NSML will develop lentigines, but it is a classic feature of the syndrome along with other issues.
There are many symptoms of a disease. They range from mild to serious.
Symptoms may include:
- Certain facial features: wide-set eyes, low-set ears, broad nose and forehead, small jaw
- Eye conditions: ptosis (drooping eyelids), wide distance between eyes, amblyopia (lazy eye), astigmatism, squinting
- Hearing problems: hearing loss (specifically, sensorineural deafness)
- Cardiovascular issues: pulmonic stenosis (heart valve issue), irregular heart rhythm, atrial or ventricular septal defects, hypertrophic cardiomyopathy (thickening of the heart muscle)
Other issues, such as:
- Musculoskeletal issues: atypical curvature of the spine (kyphosis, scoliosis), abnormalities of the breastbone or elbows
- Blood issues: blood clotting problems leading to increased bruising/bleeding, atypical white blood cell count
- Lymphatic conditions: lymphedema (buildup of fluid in the lymphatic system)
- Reproductive issues: undescended testes and infertility in males
- Kidney conditions: absence of a kidney, for example
- Skin conditions: loose skin on neck, thick skin on palms of hands, benign tumors on the skin, black/brown spots on the skin (lentigines are similar to liver spots)
There are concerns about the development of the brain.
- Growth issues: short stature apparent around child’s second birthday (without treatment, the average adult height for females with Noonan syndrome is 5 feet and 5 feet and 3 inches for males)
- Learning disabilities: some people with Noonan syndrome may experience mild learning disabilities or lower IQ.
- Other issues: problems with feeding and behavior are other possibilities, though they’re less common
It can be inherited from a parent or spontaneously during conception.
There are eight genes that can be linked to the syndrome. The five genes that have the most associated with the disorder are:
- The name of the company is PTPN11.
- The person is called “Soss 1.”
- The name of the game is RAF1
However, in 1 out of every 5 people with Noonan syndrome, no specific gene change can is ever found. And an individual’s symptoms tend to relate to the gene change responsible for the syndrome.
For example, the The name of the company is PTPN11. gene, which is found in around 50 percent of people with Noonan syndrome, is associated with pulmonic stenosis.
About 30 to 75 percent of people with Noonan syndrome inherit it from a parent who carries a gene mutation. This means that the parent with the gene mutation also actually has Noonan syndrome, too, but their symptoms may be so mild that they’ve never been diagnosed or may have been misdiagnosed.
The genetic variation happens randomly for other people with Noonan syndrome.
“Your child’s doctor may observe certain physical signs at birth. A blood test can be used to confirm a diagnosis.”
A negative blood test doesn’t always mean that a child doesn’t have Noonan syndrome, though. In 1 out of 5 cases, no genetic mutation is found.
As your child grows, you may need to order more tests to look at health issues. They include:
- heart tests, like electrocardiogram or echocardiogram
- blood tests to assess clotting factors
- eye tests and hearing tests
- educational assessments to assess developmental delays
You may also be able to get a diagnosis during pregnancy. If you suspect that you or your partner carry the gene mutation, your doctor may suggest genetic testing, like amniocentesis or chorionic villus sampling.
An ultrasound scan can also identify certain signs, like excess amniotic fluid (polyhydramnios) or fluid buildup in other parts of the body.
Questions for your doctor or healthcare professional
If your child has been diagnosed with a syndrome, you may have a lot of questions. You should write them down before your next appointment.
Questions might include:
- “Should I be tested for genetic conditions before or during my baby’s birth?”
- What are the risks of testing?
- “Do my child’s symptoms suggest that he has a syndrome?”
- What more testing is needed?
- “What are my child’s health and development concerns?”
- What treatments are available?
- What doctors should I see after my child is born?
- Where can I find more information?
Treatment for the syndrome is focused on addressing specific health conditions or symptoms.
Treatment can include surgery, medication, doctor appointments, and more.
Treatment may include:
- surgery to address congenital heart disease, like pulmonary stenosis and septal defects
- Hypertrophic cardiomyopathy is a heart issue.
- Regular appointments to check the heart.
- medication (growth hormone) for restricted growth
- speech therapy for feeding and speech issues
- Undescended testicles can be operated on.
- glasses or surgery to address eye issues
- Treatments and appointments are necessary for hearing issues.
- Treatment is needed for the Lymphatic issues.
- It helps with blood clotting.
- early intervention (physical and occupational therapy) and other therapies to address learning disabilities and other developmental delays
“You will need to work with your child’s doctors to treat any health issues. It is helpful if your doctors can work together to make sure your child is well cared for.”
The medical team that may treat a child with Noonan syndrome
Treatment for Noonan syndrome usually involves a team approach with doctors and specialists from different medical disciplines. The medical team your child has may include some professionals.
- Maternal-fetal medicine specialists: doctors who specialize in high-risk pregnancies
- Neonatologists: doctors who treat babies in the NICU after birth
- Pediatricians: primary care doctors who treat children specifically
- Pediatric cardiologists: doctors who treat heart conditions in children
- Pediatric hematologists: doctors who treat blood conditions in children
- Pediatric endocrinologists: doctors who treat hormone and growth conditions in children
- Pediatric ophthalmologists: doctors who treat eye conditions in children
- Genetic counselors: professionals who diagnose and provide information about inherited disorders
Many children with Noonan syndrome are likely to live healthy lives as they grow up.
“It is important to note that new symptoms or medical issues don’t typically develop as kids get older.”
The outlook is very individual for each child who is affected by Noonan syndrome. Left ventricular disease is a congenital heart defect and is the most concern with regard to adverse health outcomes.
Parents who carry the gene mutations associated with Noonan syndrome have a 50 percent chance of passing along the mutation with each pregnancy.
If you have a family history of the disorder, you may want to see a genetic counselor to see if you have a chance.
If you don’t have a family history of the disorder and you have one child with Noonan syndrome, your chances of encountering it again are much lower. Fewer than 1 percent of couples in which neither parent has Noonan syndrome go on to have another child with the condition.
As far as what causes Noonan syndrome to begin with, scientists aren’t so sure. There’s currently no research to suggest that it’s caused by exposure to radiation, diet, or any other environmental factors.
“Many children with Noonan syndrome can live full, healthy lives with the right treatment. You don’t have to do it on your own.”
“For help finding additional resources, contact your child’s doctor.”
The Noonan Syndrome Foundation is another great source for information, education, and advocacy.