Noonan Syndrome

Noonan Syndrome is a genetic developmental disorder. It is one of the most common genetic diseases and occurs equally in girls and boys. There is currently no curative therapy. The treatment of Noonan syndrome therefore focuses on relieving the symptoms.

Noonan Syndrome

What is Noonan Syndrome?

Noonan Syndrome is a developmental disorder caused by a genetic defect. The altered gene is located on chromosome number 12. The gene mutation is inherited, but it can also arise naturally. See aviationopedia for Epidemic Keratoconjunctivitis Explanations.

It causes various malformations of internal organs and appearance. The symptoms are similar to those of Ullrich-Turner syndrome, which is why the disease is also known as pseudo-Turner syndrome.

Along with Down syndrome, Noonan syndrome is one of the most common diseases with a genetic cause and was first described in the 1960s. The disorder was named after the doctor Jacqueline Noonan. Noonan syndrome affects both boys and girls.


The cause of Noonan syndrome is a change in a gene on the 12th chromosome. However, what triggers this mutation has not yet been researched. In about half of all cases of Noonan syndrome, the genetic defect is inherited in an autosomal dominant manner. This means that even if only one parent carries the defective gene and passes it on, the child will get the disease.

In the remaining cases, the genetic defect arises sporadically (accidentally), which means that the parents themselves do not carry an altered gene, but the defect first develops in the child. Noonan syndrome also occurs in children whose parents are both healthy.

Symptoms, Ailments & Signs

About 80 percent of all those affected have a congenital heart defect. The intellectual development of children with Noonan syndrome is usually average; around a third of those affected experience learning difficulties, especially in the area of ​​language and expression. The remaining symptoms of Noonan syndrome are externally visible:

Nearly 95 percent of those affected have widely spaced eyes. An additional eyelid crease (Mongolian crease) may appear. Other possible changes to the eye are squinting, slanting lid axes, drooping upper lids and astigmatism. The ears are set low and may be tipped back; some sufferers are hard of hearing. The jaw and face can also be altered. Wide nostrils are possible.

The philtrum (groove between the nose and upper lip) is often prominent in children with Noonan syndrome. The jaw can be too small, which leads to misaligned teeth. When the set eyes, deformed ears and small jaws come together, the impression of a triangular face is created. The hairline can be deep. The hair is often curly to frizzy.

The neck may be widened with skin folds in Noonan syndrome, but this is less common than in Turner syndrome. Growth delays and short stature are possible, but not very noticeable in Noonan syndrome. Some patients suffer from scoliosis. The nipples are often far apart. A funnel chest may occur. In boys, external sexual characteristics are sometimes underdeveloped, and cryptorchidism is common.

Diagnosis & History

The symptoms of Noonan syndrome are varied. The typical characteristics of the external appearance are a large head with a small face, a high forehead and large ears that are set low. The eyes are slanted and wide apart (hypertelorism), often the eyelids droop.

The bridge of the nose is very flat, the neck thick and short. Noonan syndrome causes short stature. There are malformations in the internal organs, most commonly in the heart and kidneys. In boys, the sexual organs often do not develop properly. Sometimes only one testicle forms or there is undescended testicles.

Some of the patients have a slight intellectual disability. Hearing and vision problems can also occur. Since the symptoms are very diverse and vary from case to case, a diagnosis based on the physical signs is difficult. With the help of a blood or genetic test, the defective gene that causes Noonan syndrome can be reliably detected.


Unfortunately, no direct or causal treatment is possible for Noonan syndrome. The symptoms can only be alleviated symptomatically, so that a complete healing usually does not occur. Patients suffer from various developmental disorders. This results in short stature and various malformations in the patient. In many cases, those affected by Noonan syndrome suffer from teasing or bullying.

Children and young people in particular are affected by these symptoms. Due to the developmental disorders, patients are in many cases also dependent on the help of other people in their lives. Even in adulthood, this can lead to difficulties or complaints in everyday life. Furthermore, Noonan syndrome can also lead to mental retardation, so that those affected are underdeveloped and require special care.

This sometimes leads to hearing problems or visual problems. Heart defects can also occur and may reduce the patient’s life expectancy. Treatment of Noonan syndrome is not associated with complications. Individual complaints can be corrected in some cases. However, those affected are dependent on various therapies throughout their lives.

When should you go to the doctor?

Persons suffering from Noonan syndrome must be closely monitored and treated by a doctor. This is particularly necessary in the later stages of the disease, when the malformations increasingly affect the patient’s physical condition. In addition, various side effects can occur in the course of life, which must be recognized early and treated accordingly. A doctor’s visit is necessary when unusual symptoms occur that affect well-being and do not go away on their own within a few days.

Due to the effects of the disease on the hormonal balance, mental problems often occur. In addition, the late onset of puberty can lead to psychological problems that need to be treated therapeutically. Affected persons should be presented to a psychologist at an early stage . Education about the disease and its possible consequences should be given in childhood. It may be useful to visit a specialist center for genetic diseases.

The physical symptoms are treated by various specialists. The malformations have to be corrected surgically. Visual problems should be treated by an ophthalmologist. Postural problems and major deformities are best presented to an orthopedist. Finally, dietary measures should be discussed with a nutritionist to aid healing and minimize the occurrence of further complications.

Treatment & Therapy

There is no curative therapy for Noonan Syndrome as the condition is caused by a defective gene. The treatment focuses purely on the symptoms. In most cases, the malformations of the internal organs, especially the heart, are the focus of therapy.

Heart defects are very often corrected in an operative procedure, usually a heart valve has to be replaced or a vascular constriction widened. Attempts are made to treat short stature by administering growth hormones. However, it must be noted that these hormones can also have a damaging effect on the heart. Therefore, careful and regular examinations of the patients during treatment are necessary.

The hearing and vision disorders can be largely remedied with glasses and hearing aids. If the children are mentally handicapped, they need special early support and therapeutic support. There is often a delay in language development and articulation difficulties that can be treated with speech therapy. Physiotherapy is also used, since the patients usually have increased muscle tension and the joints are overstretched.

These problems often require orthopedic treatment. Some of the affected children have behavioral problems, and occupational therapy can improve their behavior. Boys affected by Noonan syndrome often need surgical correction of the genitals.

Outlook & Forecast

The prognosis of Noonan syndrome is described as unfavorable. According to the current state of research and science, there is no therapy that leads to a cure or full recovery. A genetic defect was identified as the cause of the disease. Since it is not permitted by law to change human genetics in any way, no causal treatment can take place.

The doctor treating you concentrates on the individually strong symptoms and develops an appropriate treatment plan. This is adapted and changed depending on the further development of the child. The aim is to improve the patient’s quality of life and optimize well-being. The earlier a diagnosis can be made, the sooner therapy can begin.

Early intervention programs show good results. Nevertheless, the disease is associated with a developmental disorder. Despite all efforts, there are difficulties in coping with everyday life and optical abnormalities. In addition, most of those affected have a congenital heart defect. This can develop into a life-threatening condition at any time.

Due to the changed appearance and the general burden of the disease, the risk of developing a mental disorder is increased. In many cases, the functional activity of seeing or hearing is restricted. In some patients, visual aids and hearing aids can help to significantly improve the symptoms.


Noonan Syndrome is unpreventable because it is caused by a genetic defect. With the help of genetic tests, parents can have a genetic check carried out before they become pregnant. However, Noonan syndrome can occur in the child even if both parents are healthy because the gene mutation can develop on its own.


In most cases, those affected with Noonan syndrome have only very few and only very limited follow-up measures available. In this case, a doctor must be consulted at an early stage so that further complications or other complaints do not arise for the person concerned. Noonan syndrome cannot heal on its own.

The sooner a doctor is contacted, the better the further course of the disease will usually be. If there is a desire to have children, a genetic examination and counseling can be carried out so that the syndrome does not appear again in the offspring. Those affected are dependent on intensive and comprehensive care and support from their own family and friends.

Children, in particular, need to be clearly encouraged so that they can continue to develop according to their age and to prevent problems in adulthood. It is not uncommon for regular checks and examinations by a doctor to be necessary in order to monitor the symptoms of the syndrome over the long term. In many cases, this disease reduces the life expectancy of those affected.

You can do that yourself

Noonan syndrome is associated with various cognitive impairments. Patients can still lead a symptom-free life if they take a few measures into account. First of all, it is important to get comprehensive advice from a specialist. This can give tips for everyday life and refer the patient to a physiotherapist who supports the therapy.

Furthermore, sick people have to contact a self-help group. Talking to other sufferers makes it easier to understand and accept the illness and is also a good opportunity to learn new measures for dealing with the illness. The sick have to organize various aids, for example walking aids or special glasses, in order to cope with everyday life. Since there is still an increased risk of falls and accidents, family members should stand by to provide support. A nurse can also be called in if Noonan syndrome is pronounced.

The genetic disease takes a progressive course, which is why the medication and therapy in general always have to be adjusted. Patients or their parents should consult the doctor responsible for this. The medicinal treatment can be supported by natural painkillers as well as massages and methods from Chinese medicine.