Noonan syndrome is a genetic developmental disorder. It is one of the most common genetically caused disorders and occurs equally in girls and boys. There is currently no curative therapy. Therefore, treatment for Noonan syndrome focuses on alleviating symptoms.
What is Noonan syndrome?
Noonan syndrome is a developmental disorder caused by a genetic defect. The altered gene is located on chromosome No. 12. The gene mutation is inherited, but it can also occur on its own. 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 called pseudo-Turner syndrome. Noonan syndrome is one of the most common disorders with a genetic cause, along with Down syndrome, and was first described in the 1960s. The disorder was named after the physician Jacqueline Noonan. Noonan syndrome occurs in both boys and girls.
Causes
The cause of Noonan syndrome is a change in a gene on the 12th chromosome. However, what causes 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 is a carrier of the defective gene and passes it on, the child will develop the disease. In the remaining cases, the genetic defect develops sporadically (by chance), i.e. the parents themselves do not carry an altered gene, but the defect develops in the child. Noonan syndrome thus occurs even in children whose parents are both healthy.
Symptoms, complaints, and signs
About 80 percent of all affected individuals have a congenital heart defect. The mental development of children with Noonan syndrome is usually average; about one-third of those affected experience learning difficulties, especially in speech and language. The remaining symptoms of Noonan syndrome are externally visible:
Nearly 95 percent of affected individuals have wide-set eyes. An additional eyelid crease (Mongolian wrinkle) may occur. Other possible eye changes include strabismus, tilted eyelid axes, drooping upper eyelids, and corneal curvature. The ears set low and may be tilted back; some affected individuals have hearing loss. The jaw and face may also be altered. Wide nostrils are possible. In children with Noonan syndrome, the philtrum (groove between the nose and upper lip) is often prominent. The jaw may be too small, resulting in misaligned teeth. If eyes that are set apart, deformed ears and small jaw come together, the impression of a triangular face is created. The hairline may be low. 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 retardation and short stature are possible, but are not very noticeable in Noonan syndrome. Some patients suffer from scoliosis. The nipples are often widely spaced. A funnel chest may occur. In boys, external sexual characteristics are sometimes underdeveloped, and cryptorchidism is common.
Diagnosis and course
The symptoms of Noonan syndrome are varied. The typical features on 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 root of the nose is very flat, and the neck is thick and short. Noonan syndrome causes short stature. There are malformations of the internal organs, most often the heart and kidneys. In boys, the sexual organs often do not develop properly. Sometimes only one testicle is formed or there is undescended testicle. In some patients there is a mild mental retardation. Furthermore, hearing and vision disorders may 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.
Complications
Unfortunately, direct or causal treatment is not possible for Noonan syndrome. In this case, the symptoms can only be alleviated symptomatically, so a complete cure usually does not occur. Patients suffer from various developmental disorders in this case.This results in short stature and various malformations in the patients. In many cases, those affected by Noonan syndrome suffer from teasing or bullying. Children and adolescents are particularly affected by these complaints. Due to the developmental disorders, in many cases the patients are also dependent on the help of other people in their lives. Even in adulthood, this can lead to difficulties or discomfort in everyday life. Furthermore, Noonan syndrome can also lead to mental retardation, so that the affected persons are underdeveloped and require special care. Hearing or vision problems may occur. Heart defects may also occur, possibly reducing the patient’s life expectancy. Noonan syndrome treatment is not associated with complications. The individual symptoms can be corrected in some cases. However, affected individuals are dependent on various therapies throughout their lives.
When should you see a doctor?
Individuals affected with Noonan syndrome must be closely monitored and treated by a physician. This is particularly necessary in the later stages of the disease, when the malformations increasingly affect the patient’s physical condition. In addition, various concomitant symptoms can occur in the course of life, which must be recognized at an early stage and treated accordingly. A visit to the doctor is necessary if unusual symptoms occur that affect well-being and do not subside on their own within a few days. Due to the effects of the disease on the hormonal balance, psychological complaints often occur as well. In addition, the delayed onset of puberty can lead to psychological complaints that require therapeutic treatment. Affected individuals should be introduced to a psychologist at an early stage. Education about the disease and its possible consequences should take place in childhood. For this purpose, it may be useful to visit a specialist center for genetic diseases. The physical symptoms are treated by different specialists. For example, malformations must be surgically corrected. Vision problems need to be treated by an ophthalmologist. Postural defects and major deformities are best presented to an orthopedist. Last, dietary measures should be discussed with a nutritionist to support the healing process and minimize the occurrence of further complications.
Treatment and therapy
There is no curative therapy for Noonan syndrome because the condition is caused by a defective gene. Thus, treatment focuses purely on the symptoms. Usually the malformations of the internal organs, especially the heart, are the main focus of the therapy. Very often, heart defects are corrected in a surgical procedure, usually a heart valve has to be replaced or a vasoconstriction widened. Treatment of short stature is attempted by administering growth hormones. However, it should be noted that these hormones can also have a damaging effect on the heart. Therefore, careful and regular examinations of the patients are necessary during the treatment. The hearing and vision disorders can be remedied as far as possible with glasses and hearing aids. If the children are mentally handicapped, they require special early intervention and therapeutic support. Often there is a language development delay and articulation difficulties, which can be treated with logopedic therapy. Physiotherapy is also used, as patients usually have increased muscle tension and hyperextended joints. Orthopedic treatment is also often necessary for these problems. Some of the affected children have behavioral problems, and here occupational therapy can be used to improve behavior. In boys affected by Noonan syndrome, surgical correction of the sex organs is often necessary.
Outlook and prognosis
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 complete recovery. A genetic defect has been identified as the cause of the disease. Since it is not allowed to change the genetics of humans in any form due to legal regulations, no causal treatment can take place.The attending physician focuses on the individually severe complaints and develops an appropriate treatment plan. This is adapted and modified depending on the child’s further development. 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 as well as visual 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 altered appearance as well as the general stress of the disease, the risk of developing a mental disorder is increased. In many cases, functional vision or hearing is impaired. In some patients, visual aids as well as hearing aids can help significantly improve symptoms.
Prevention
There is no way to prevent Noonan syndrome because it is caused by a genetic defect. With the help of genetic testing, parents can have a test done before becoming pregnant to see if they have a gene mutation. However, Noonan syndrome can occur in the child, even if both parents are healthy, because the gene mutation can develop on its own.
Follow-up
Affected individuals with Noonan syndrome have very few and also very limited aftercare measures available to them in most cases. In this case, a physician must be consulted at an early stage to prevent further complications or other complaints in the affected person. There is no independent cure for Noonan syndrome. The earlier a doctor is contacted, the better the further course of the disease usually is. If there is a desire to have children, genetic testing and counseling can be done to prevent the syndrome from recurring in descendants. Those affected are dependent on intensive and comprehensive care and support from their own family and friends. Children, in particular, require significant support so that they can continue to develop in a manner appropriate to their age and to prevent symptoms in adulthood. Not infrequently, regular check-ups and examinations by a physician are necessary in order to permanently monitor the symptoms of the syndrome. In many cases, this disease reduces the life expectancy of the affected person.
What you can do yourself
Noonan syndrome is associated with various cognitive impairments. Patients can still lead a symptom-free life if they consider some measures. First of all, it is important to have a comprehensive consultation with a specialist. He or she can provide tips for everyday life and refer the sufferer to a physiotherapist who can support the therapy. Furthermore, sufferers must turn to a self-help group. Talking to other sufferers makes it easier to understand and accept the disease and is also a good way to get new measures for dealing with the disease. Sufferers need to organize various aids, for example walking aids or special glasses, to cope with everyday life. Nevertheless, since there is an increased risk of falls and accidents, relatives should be on hand to provide support. A caregiver may also be called in if Noonan syndrome is pronounced. The genetic disease takes a progressive course, which is why medication and therapy in general must always be adjusted. For this purpose, the patients or their parents should consult the responsible physician. Medication can be supported by natural painkillers as well as massages and methods from Chinese medicine.
