Smith-Magenis Syndrome

By | June 10, 2022

Smith-Magenis syndrome is the name of a rare hereditary disease. It is caused by a loss of a piece of chromosome 17.

What is Smith Magenis Syndrome?

Smith-Magenis syndrome ( SMS ) is a rare genetic disease. Affected people are missing a tiny piece of chromosome 17. However, this small section is important because it contains information that is important for the healthy development of the child in the mother’s womb.¬†For what does ncl mean, please visit

Smith-Magenis syndrome is named after the two genetics specialists Ann Smith and Ellen Magenis. The doctors first described the disease in the early 1980s. According to American studies, the prevalence of Smith-Magenis syndrome is 1:25,000 births. In German-speaking countries, the disease has so far only appeared occasionally. There are no gender differences in the occurrence of the syndrome.


Smith-Magenis Syndrome is caused by the lack of a tiny part of chromosome 17, which means that the information found there is also missing. In medicine, the absence of this data is referred to as a 17p11.2 deletion. The p stands for “Petit”, which means “small” and indicates the short chromosome arm.

How much of the chromosome piece is missing varies from person to person. For this reason, the intensity of Smith-Magenis syndrome also varies. There are several genes in the missing part of the chromosome. However, the symptoms of Smith-Magenis syndrome are primarily caused by the absence of the RAI1 gene.

Some physicians suspect that the absence of the other genes contributes to individual differences in disease characteristics. Scientific studies are still being carried out on the exact connections. According to current scientific knowledge, there are no risk factors such as environmental influences or misconduct on the part of the mother during pregnancy.

This is how Smith-Magenis syndrome develops spontaneously. The mutation on the 17th chromosome is caused by chance and starts before fertilization. A mutation is possible in both the mother and the father. However, it is quite possible that the children of affected parents remain healthy despite the deletion on chromosome 17 and do not automatically become ill.

Symptoms, Ailments & Signs

Smith-Magenis syndrome is accompanied by a variety of typical behavioral problems. These include developmental abnormalities such as moderate to severe mental development disorders. These are mostly delays in language development and general developmental retardation.

Since Smith-Magenis syndrome is a dysmorphic syndrome, there are also dysmorphological abnormalities such as brachycephaly (short-headedness), midface hypoplasia, broad and short hands, deep-set eyes, arched upper lips, downward-pointing corners of the mouth, deep-set ears and a wide bridge of the nose.

Furthermore, there are behavioral problems that cannot always be recognized to a sufficient extent in small children. Those affected injure themselves by hitting their heads against the wall, biting their fingers or hands and pulling out their toenails or fingernails.

The pain is felt to be reduced. Because the day-night rhythm is also disturbed, the patients suffer from pronounced sleep disorders. In addition, health problems such as sensorineural or conductive hearing loss, short stature or scoliosis occur.

Furthermore, there are changes in the eyes such as short-sightedness, squinting or a cornea that is too small, a heart defect, epilepsy, brain abnormalities such as ventriculomegaly or problems with the urinary bladder.

A deep and rough voice, tiredness during the day, low thyroid hormone levels and a reduced immunoglobulin level are also typical. Furthermore, many of those affected behave like autistic people, are unable to speak, go about their daily routine and are afraid of being touched. Aggressive behavior and even outbursts of anger are not uncommon.

Diagnosis & course of disease

Since the symptoms of Smith-Magenis syndrome are extremely extensive, they are not sufficient for an exact diagnosis of the disease. There are some diseases that are similar to Smith-Magenis syndrome. These include Prader-Willi syndrome. Counting and looking at the chromosomes is also considered insufficient for a reliable diagnosis.

For this reason, the doctor conducts a genetic test. This procedure is called the FISH test (fluorescence in situ hybridization). In this procedure, some blood is taken from the patient to examine the blood cells for the absence of certain components of chromosome 17.

Smith-Magenis syndrome is difficult to diagnose. It is assumed that this circumstance contributes to the low number of cases. It is not uncommon for many affected children to receive a different diagnosis, even though they are suffering from SMS. These are mostly ADHD (Attention Deficit Hyperactivity Disorder) or autism.

Smith-Magenis syndrome is considered incurable. The course of the disease depends on its extent, the age of diagnosis and appropriate therapeutic measures. Some patients can live to be more than 80 years old.


Due to Smith-Magenis Syndrome, patients suffer from various mental and physical ailments and limitations. In many cases, the relatives or parents are also affected by this syndrome and need psychological support and treatment. Those affected suffer from severe developmental disorders and behavioral problems.

They need special support and usually also help in their everyday life. The urge to self-injure can also become noticeable due to illness, so that treatment in a closed clinic may also be necessary. There are also problems sleeping or hearing loss. Due to short stature, bullying or teasing can occur, especially among young people.

Those affected also suffer from visual disturbances and a heart defect. In severe cases, epileptic seizures can also occur, which can lead to death. Due to the severe symptoms, life expectancy is usually significantly reduced. Treatment of the syndrome is purely symptomatic. Unfortunately, it is not possible to limit all complaints completely. Unfortunately, prevention of Smith-Magenis syndrome is not possible.

When should you go to the doctor?

Treatment by a doctor is always necessary for Smith-Magenis syndrome. Since this is a hereditary disease, it cannot be completely cured, so that those affected usually depend on lifelong therapy to alleviate the symptoms. If the person concerned wishes to have children, genetic counseling can also be carried out to prevent the Smith-Magenis syndrome from being passed on to the descendants.

A doctor should be consulted for this syndrome if the person affected suffers from severe developmental disorders or shows severe behavioral problems. Those affected are very restless and cannot concentrate. In many cases, self-injurious behavior also indicates Smith-Magenis syndrome and should always be evaluated by a doctor. Furthermore, the patients often show eye problems or heart defects. If you have these symptoms, you should also see a doctor.

Smith-Magenis syndrome can be diagnosed by a general practitioner . Further treatment is then carried out by the respective specialist and depends heavily on the severity of the symptoms.

Treatment & Therapy

Because Smith-Magenis syndrome is caused by genetics, there is no cure. For this reason, the treatment of the disease is limited to the symptoms. Speech therapy, ergotherapy and physiotherapeutic measures are considered helpful.

Communication training that includes sign language is also considered useful. Despite all therapeutic measures, most patients need help throughout their lives. Certain medications can also be given to treat the symptoms of Smith-Magenis syndrome.

This can alleviate some symptoms. The administration of the hormone melatonin improves sleep disorders. Other medications, such as Risperidal, can be used to counteract self-injurious behavior.


Smith-Magenis syndrome is a genetic disease. Prevention is therefore not possible.

You can do that yourself

The symptoms of the hereditary disease become apparent immediately after birth. Naturally, infants cannot initiate sufficient self-help measures. In addition, the health impairments are so diverse that it is not possible for those who are ill to improve the situation to a sufficient extent.

Relatives are therefore obliged to organize the structure of everyday life and care of the patient optimally in the interests of the patient. Since self-destructive acts occur, the person concerned must be protected from himself. Otherwise, there can be serious complications and deterioration in health. Since relatives are often overwhelmed with the care of the patient, good care should be used if necessary. At the same time, a stable social environment is important so that the patient is not exposed to any additional stress.

A large number of patients suffer from a disturbed sleeping and waking rhythm. This represents a special challenge for everyone involved. The behavioral problems are also not always easy to handle in everyday life. As soon as loved ones reach their emotional and physical limits, they should make changes. The organization of leisure time or the use of psychotherapeutic support can help to experience a corresponding balance. Dealing with the disease is often so stressful that otherwise psychological complications occur.


Aftercare for Smith-Magenis syndrome (SMS) is basically aimed at treating the symptoms of the disease. Because texting is genetic. A cure is not possible. The scope of follow-up treatments and follow-up examinations can be very complex in SMS.

The spectrum of possible symptoms ranges from physical abnormalities and developmental delays (both physical and mental) to severe behavioral disorders, mental retardation and serious diseases of the internal organs. The symptoms caused by SMS generally do not heal. The task of aftercare is to achieve and maintain the highest possible quality of life for people suffering from SMS.

The focus of the follow-up treatments is therefore the continuation of the therapeutic intervention. As a result of the follow-up care, children and young adults suffering from SMS must have learned in particular to live with the symptoms of the disease in the best possible way. In addition to lifelong drug treatment, medical treatments (repeating regularly) are also prescribed by doctors as well as cures and speech therapy, occupational therapy and music therapy treatments.

As a self-help measure, relatives can create a stable social environment for the person suffering from SMS during aftercare and optimally structure everyday life in the interests of the patient. If the symptoms worsen, follow-up examinations by specialists may be necessary.

Smith-Magenis Syndrome