The main symptom of Muenke syndrome is craniosyostosis of the coronary suture, which is due to a mutation in the FGFR3 gene. The disease is inherited in an autosomal dominant manner and is often associated with abnormal extremities. The treatment usually corresponds to an operation.
What is Muenke Syndrome?
In craniosynostosis, one or more cranial sutures ossify prematurely during embryonic development, thereby preventing the physiological growth of the skull and brain. Many diseases from the group of congenital malformation syndromes with predominant involvement of the face contain such craniosyostoses. One such disease is coronary suture synostosis syndrome, also known as Muenke syndrome. See foodezine for Everything about CHIME Syndrome.
The disease was first described in 1997. M. Muenke and colleagues are considered the first to describe it. Muenke syndrome is characterized by craniosynostosis of the coronary suture and also includes skeletal changes in the tarsal and carpal bones. The prevalence of the syndrome is not yet known. The manifestation occurs in the early neonatal period or at the latest in early infancy. Although the disease has not been conclusively researched, the cause has now been elucidated.
Causes
In many cases, Muenke syndrome has been associated with familial accumulation. In these cases, the inheritance most closely corresponds to an autosomal dominant inheritance. However, cases have also been documented in which the syndrome appears to have occurred sporadically. The cause seems to be a genetic mutation, which in the sporadic cases probably corresponds to a new mutation. The location of the mutation is also considered to have already been identified.
Specifically, the disease is said to be based on mutations in the FGFR3 gene, which can be found at gene locus 4p16.3. Other syndromes have also been linked to the FGFR3 gene. An example of this is the so-called Apert syndrome. The gene codes for the fibroblast growth factor receptor 3 within the DNA. Little is known about the physiological effects of the FGF-3 growth factor.
According to speculation, FGF-3 is a decisive factor, especially for the embryonic period. The mutation of the receptors presumably means that the growth factor does not bind adequately during embryonic development.
Symptoms, Ailments & Signs
Patients with Muenke syndrome suffer from various symptoms. Due to the premature closure of their coronary suture, those affected have an abnormal head shape, which is also noticeable in facial anomalies. In addition to a shortened anterioposterior skull diameter, there are usually reduced deep orbits.
These symptoms are often associated with hypoplasia of the maxilla. If there is a unilateral closure of the coronary suture, the orbits on the corresponding side are flattened. As a rule, the intelligence of the patients is not affected by the syndrome. Fusions of hand bones or tarsal bones are found on the limbs. Malsegregation is also conceivable at the carpal bones.
Cone epiphyses are also among the possible symptoms. In some cases, the clinical picture of the patients is additionally associated with osteochondromas. Phenotypic and thus symptomatic overlap with other syndromes such as Pfeiffer syndrome, Jackson-Weiss syndrome or Saethre-Chotzen syndrome are clinically conceivable manifestations.
Diagnosis & course of disease
The diagnosis of Muenke syndrome is usually made in the neonatal period, since the disease can be detected early on with visual diagnostics. About one patient in 15,000 newborns suffers from coronary synostosis. However, this phenomenon does not have to be automatically attributed to Muenke syndrome.
Therefore, the diagnosis requires the detection of the pathogenic mutation in the FGFR3 gene. Patients’ hands and feet may appear normal radiographically, so looking for abnormalities is not sufficient for diagnosis. In principle, all children with coronary synostosis can be examined for the specific P250R mutation.
This examination corresponds to a molecular genetic analysis. The exclusion of the mutation does not necessarily mean that the patient does not have Muenke syndrome. In a few cases, the mutation could not be detected in those affected. However, the proof is regarded as conclusive for the diagnosis. The prognosis is less favorable for female patients.
Complications
Muenke syndrome causes those affected to suffer from various malformations and malformations, which mainly occur on the patient’s head and face. These deformities often lead to psychological problems and depression. Those affected often suffer from inferiority complexes and reduced self-esteem.
There are often feelings of shame due to the symptoms and children in particular can be affected by bullying and teasing by Muenke syndrome. However, the intelligence is not impaired, so the mental development of the patients progresses without complications. There are also deformities in the limbs, so that there may be limitations in various activities or restricted movement in everyday life.
The quality of life is significantly reduced by Muenke syndrome. There are no further complications in the treatment of Muenke syndrome. As a rule, no causal treatment is possible, but some surgical interventions must be carried out in order to avoid further consequential damage.
The life expectancy of those affected is usually not limited. The treatment can also take place immediately after the birth. In some cases, the children’s parents are also affected by mental health problems caused by Muenke syndrome.
When should you go to the doctor?
The characteristic deformities in the head and face are clear indications of Muenke syndrome and usually lead to a diagnosis immediately after birth. In the case of mild symptoms, the doctor responsible should be informed of any symptoms. In isolated cases, hand or foot root bones can grow together, resulting in the gait typical of the disease. People who already have a case of the disease in their family should arrange for a genetic test at an early stage. The necessary treatment steps can then be initiated immediately after the birth.
Parents of affected children should also inform the family doctor about new symptoms and any other abnormal behavior of the child. In addition, close monitoring by a specialist is always necessary. Treatment usually takes place in a hospital or in a clinic specializing in genetic diseases. In addition to the general practitioner, the orthopedist or an internist can be consulted. In the case of chronic complaints, therapy and physiotherapy are also part of the treatment.
Treatment & Therapy
Causal treatment is not available for patients with Muenke syndrome. Gene therapy approaches offer hope for a causal therapy, but these have not yet reached the clinical phase. The treatment is purely symptomatic and depends on the symptoms in the individual case. Surgical treatment options are the only options for correcting the skull anomalies.
The surgical procedure is designed to help relieve the pressure on the brain caused by the early closure of the coronary suture. The cranial nerves are relieved in this way and are ideally less compressed or not compressed at all after the procedure. A conservative treatment option is available for less severe craniosynostosis. For example, children who are more easily affected can get skull shapes that they have to wear in the long term.
These skull shapes try to model the skull sufficiently. Since Muenke syndrome is usually diagnosed in newborns, such a conservative remodeling is particularly useful: the head shape of infants is still adaptable. The conservative post-modeling ultimately has the same goal as the operative modeling.
A physiological brain growth should be made possible by the treatment. In addition, the appearance of the head is adjusted to the average. Accompanying symptoms such as malformations of the extremities can be treated surgically. If they do not restrict or hinder the person concerned, such treatment is not mandatory.
Outlook & Forecast
Muenke syndrome is a rare disease, but it can now be effectively treated surgically. If the premature closure of the coronary suture is recognized in time, the prognosis is good. Any malformations can be treated surgically. Appropriate medication can be prescribed for symptoms such as pain or sensory disturbances. Life expectancy is not reduced by coronary suture synostosis syndrome.
The quality of life can be slightly restricted by the above-mentioned complaints and any scars in the area of the face and head. In general, however, the prognosis is positive. Children suffering from Muenke syndrome are particularly susceptible to sensorineural hearing loss. Poor hearing can lead to problems, especially later in life, when the patient is no longer able to understand instructions or find their way around in everyday life, for example.
As a result of exclusion and reduced self-esteem, some of the sufferers develop mental health problems. Well-being can be reduced if sufferers do not have a good network of support in the form of parents, relatives, friends and therapists. Children who suffer from Muenke syndrome always need support in everyday life in order to stay mentally and physically healthy despite the illness.
Prevention
Muenke syndrome cannot be prevented because it is influenced by genetic factors rather than external ones. The only preventive measure is genetic counseling during pregnancy.
Aftercare
In most cases, people affected by Muenke syndrome only have very few and only very limited direct follow-up measures available. First and foremost, a quick and, above all, early diagnosis of this disease should be made so that no further complications can occur. Since Muenke syndrome is a genetic disease, it cannot be completely cured.
If you want to have children, however, genetic testing and counseling can be useful to prevent the syndrome from reoccurring. Most of those affected require surgical intervention. The patient should definitely rest and take it easy after such an operation, ideally staying in bed. Likewise, strenuous or physical activities should be avoided in order not to unnecessarily stress the body.
In many cases, those affected by the syndrome are also dependent on the help and support of their own families in everyday life. Loving and intensive conversations with one’s own family and friends also have a very positive effect on the further course of the disease. It is not uncommon for depression or other mental disorders to be prevented in this way.
You can do that yourself
Muenke syndrome is usually treated surgically and with medication. The most important self-help measure is to take it easy on the body after the procedure and to consult closely with the responsible doctor. Parents of affected children should keep a close eye on the child and inform the doctor responsible if there are any abnormalities.
In general, Muenke syndrome can be treated relatively well and does not result in any permanent impairments in quality of life. However, deformities and malformations almost always remain, which can sometimes represent a great psychological burden for those affected. For this reason, medical treatment should be supported by therapeutic measures.
Severely affected children with developmental discrepancies were previously advised to attend a special kindergarten and later a special school. Instead, reference is now made to inclusion in mainstream schools. Children with no other abnormalities can attend normal and higher schools anyway.
Comprehensive therapy is necessary, especially in the case of severe movement restrictions. Parents can support these measures by supporting the child in everyday life. Other physiotherapeutic measures are usually indicated.
Since the disease can also be a significant burden for relatives, parents and friends should also seek therapeutic help. The therapist can also establish contact with other affected people and refer the parents to a self-help group if necessary.
