If Noonan syndrome has been confirmed or is strongly suspected, further tests are needed to establish the extent of the symptoms. These tests may include:
- an electrocardiogram (ECG) – where electrodes (small, metallic discs placed on the skin) measure the electrical activity of the heart
- an echocardiogram – an ultrasound scan of the heart
- an educational assessment
- blood tests to check how well the blood clots
- eye tests – to check for problems such as squints or blurred vision
- hearing tests – to check for problems such as hearing loss caused by a middle ear infection or damage to the cells or nerves inside the ear
Some of these tests may need to be repeated regularly after the diagnosis, to monitor the symptoms.
Diagnosis during pregnancy
If you're pregnant, it may be possible to test your unborn baby for Noonan syndrome if:
- you, your partner or a close family member has been found to carry one of the faulty genes associated with the condition
- routine ultrasound scans detect possible signs of the condition in your baby, such as polyhydramnios (an excessive amount of amniotic fluid), pleural effusion (fluid in the space around the lungs) or a build-up of fluid in certain other parts of the body
Testing for Noonan syndrome during pregnancy involves collecting a sample of your baby's DNA and checking it for any of the faulty genes associated with the condition.
This can be done using either chorionic villus sampling (where a sample of cells is removed from the placenta) or amniocentesis (where a sample of amniotic fluid is removed). Both of these tests carry around a 0.5 to 1% chance of causing a miscarriage.
If your baby is found to have one of the faulty genes, a genetic counsellor will talk to you about what the test result means and what your options are. Read more about genetic testing and counselling.