In melorheostosis, bones of the extremities thicken completely or proportionally without patients noticing. Only in rare cases do edema of the muscles, growth disturbances, or movement restrictions become apparent. Symptomatic therapy is limited to patients with actual symptoms.
What is melorheostosis?
Diseases with more specified alterations in bone density or structure are a broad group that includes many individual disorders and can present clinically with a wide variety of manifestations. One such manifestation is melorheostosis. The condition is also known as Léri syndrome and was first described in the 20th century. The Parisian neurologist André Léri is considered the first describer, and the term Léri syndrome was introduced in his honor. Melorheostosis manifests as thickening of the skeleton, usually in the extremities. The syndrome is sometimes referred to as mesenchymal dysplasia and is thus associated with abnormalities of embryonic mesenchymal tissue. Manifestation can occur at any age. With a prevalence of less than one case per 1000000 people, melorheostosis is an extremely rare condition. The clinical terms candle wax disease and wax bone disease are often used synonymously with melorheostosis and figuratively describe the structural bone changes.
Causes
Waxy bone disease probably occurs sporadically. Familial clusters have not been observed to date. Therefore, a mode of inheritance has not yet been identified and is not thought to be applicable on the basis of cases to date. Nevertheless, genetic factors appear to underlie the disease, leading to structural changes and functional impairment of bone tissue. Only recently have the bone changes been linked to a specific gene for the first time. Currently, medicine suspects a mutation in the LEMD3/MAN1 gene as the cause of the disease. This gene codes in the DNA for protein elements of the inner nuclear membrane. This is the inner part of the double-layer membrane, as it encloses the interior of cell nuclei and controls the transport of substances between the plasma and cytoplasm. Mutations of the above-mentioned gene reduce the function of the nuclear membranes and thus impede the exchange of substances between the nuclear plasma and cytoplasm. The factors causing the mutation have not yet been clarified. Possibilities include, for example, exposure to toxins or malnutrition during pregnancy.
Symptoms, complaints, and signs
Although it is a congenital disorder, most patients of melorheostosis do not show symptoms until late adulthood. Often, they remain asymptomatic throughout their lives and receive their diagnosis via an incidental finding. In other cases, the symptom complex manifests early through dermal changes. Thus, fibrosis of dermal tissue may appear on the skin over the altered bone structures. In addition, some patients show edema of the muscles over the affected bone regions, accompanied by thickening and impairment of the muscles, tendons or joints. In particular, joints so affected sometimes also evoke pain or involuntary contractures of the muscles. Somewhat less frequently, patients of melorheostosis show growth disorders because the changes in the bones bridge the growth plates, for example. All changes of melorheostosis occur preferentially in the limbs. Only in absolutely exceptional cases dermal and skeletal symptoms of the disease manifest in other localization. Some patients also symptomatically notice differences in length or deformities of the extremities.
Diagnosis and disease course
Because melorheostosis usually remains asymptomatic, it rarely brings its patients to the doctor. In most cases, the disease is detected as an incidental finding on x-ray, such as on x-rays taken as part of a bone fracture or accident. The X-ray image shows dermatoma-like limited and stripe-like sclerotizations and condensations that resemble draining drops of wax. Radiologically, the physician must rule out diseases such as osteomyelitis, osteopetrosis, osteopoikilia or Buschke-Ollendorff syndrome and scleroderma. This exclusion can take place, for example, by means of molecular genetic analysis.If evidence of mutations in the LEMD3/MAN1 gene can be obtained, the diagnosis of melorheostosis is considered confirmed.
Complications
Melorheostosis does not cause symptoms or complications in every case. In many cases, melorheostosis does not lead to symptoms, so affected individuals live with the condition throughout their lives. Even if the diagnosis is accidental, treatment does not have to be initiated in every case if the affected person does not complain of symptoms. Furthermore, melorheostosis can cause distortion of the skin or bones. This negatively affects the muscles and joints in particular, so that the patient’s movement may be disturbed. As a result, everyday life is also significantly restricted. In children, melorheostosis can lead to disturbances in growth and thus to developmental disorders. It is not uncommon for deformities of the extremities or different lengths of the extremities to occur. However, the life expectancy of the patient is not reduced by this disease. The symptoms of melorheostosis can be well limited by various therapies and therapeutic measures. In some cases, however, those affected have to live with the movement restrictions for their entire lives. It is generally impossible to predict whether a positive course of the disease will occur.
When should you see a doctor?
In melorheostosis, many patients do not experience symptoms until late adulthood. Because the condition is characterized by a lack of symptoms over a long period of time, there are no signs or warning signals for the affected person that make a visit to the doctor necessary. If the congenital disease shows first limitations of the motor function, a doctor is needed. If the affected person suffers from a reduction in muscle strength, internal weakness or swelling near the bones, a doctor should be consulted. If arms and legs can no longer be extended or flexed as usual, there is cause for concern. If there is general restriction of movement or irregularity of movement, a physician should be told of the observations. If pain of the bones, joints or tendons occurs, clarification of the cause should take place. The formation of edema or disorders of voluntary contraction of the muscles should be investigated and treated. If the general risk of accidents and injuries increases due to the complaints, a restructuring of everyday life should take place. A treatment plan is developed together with a physician. In addition, the affected person receives important information on preventive care and necessary measures during a visit to the doctor. Deformities of the bones, abnormalities of the skeletal system as well as differences in length of the extremities should be examined by a physician.
Treatment and therapy
No causal therapeutic methods are yet available for patients with melorheostosis. The disease is currently considered incurable. Although gene therapy approaches are currently being explored as causal therapeutic approaches for genetic diseases, they have not yet reached the clinical phase. Genetic diseases such as melorheostosis can therefore only be treated symptomatically at the present time. In melorheostosis, the question arises as to the benefit of such therapy. Since most patients remain asymptomatic until the end of their lives, no treatment is necessary in most cases. However, if symptoms are present, various treatment options are available. For example, movement restrictions and growth disturbances are often treated with the use of contractures and bone braces. The dermal symptoms and fibrosis of the skin do not necessarily need to be treated. In most cases, they do not affect patients further and almost never develop into serious phenomena. Thus, as long as the proliferation of connective tissue does not bother the patient, no therapy is usually applied. Symptoms such as edema of the muscles, on the other hand, should very well be treated. This treatment is always a drug therapy and may correspond, for example, to the administration of diuretics.
Outlook and prognosis
The disease melorheostosis is considered incurable so far. Genetic causes probably condition the malformation of the bones. In most cases, however, the prognosis for sufferers is positive. They remain symptom-free for the rest of their lives. The problems prove to be minor.Some scientists argue that the typical signs rarely appear after the age of 20. As a result, boys and girls in the developmental stage are considered a risk group. If symptoms occur, they can usually be successfully remedied by physiotherapy or surgery. Only in exceptional cases do doctors perform an amputation. There is no shortening of life due to melorheostosis. However, patients may have to cope with slight or severe movement restrictions. As a result, professional and private goals cannot always be fully realized. A psychological burden may occur. If therapy is dispensed with, there are usually no disadvantages. This is due to the fact that the majority of those affected notice no or only minor complaints. If, on the other hand, complications arise, medical treatment is indicated. Turning down such offers of help can promote an inability to move.
Prevention
To date, the causative factors for a mutation in the LEMD3/MAN1 gene are unknown: Even the mutation itself has only recently been linked to the disease. Until the causative factors are established, melorheostosis will not be preventable.
Follow-up
Because melorheostosis is considered incurable to date, follow-up care focuses on stabilizing quality of life. Sometimes affected individuals remain symptom-free for the rest of their lives. The problematic nature of the disease proves to be minor. Some scientists argue that the typical signs rarely appear after the age of 20. As a result, boys and girls in the developmental stage are considered a risk group. In general, those affected and their relatives are advised to adopt a healthy lifestyle with a balanced diet to support the immune system. For stabilization, the doctor will also suggest certain relaxation and mental techniques, as well as advising as many leisure activities as possible, which should provide the affected family with many enjoyable hours together. If the parents, who have already been affected once, harbor a further desire to have children, they will be advised to undergo a detailed genetic examination in order to determine in advance the likelihood of having another child with the disease.
What you can do yourself
Accompanying medical therapy, those affected can alleviate the symptoms of melorheostosis by taking a few measures and home remedies. First, general tips such as taking it easy and avoiding stress apply. Since the growth disturbances and movement restrictions are often accompanied by a low sense of well-being, appropriate countermeasures should be taken. This can be a fulfilling hobby, but also a healthy diet, exercise or a conversation with friends. Which strategies make sense in detail is best determined together with a therapist. In general, melorheostosis patients should always consult with a psychologist, who can provide further tips on how to deal with the psychological after-effects of the bone disease. Physical symptoms can be treated with the help of natural preparations. Pain can be relieved with natural remedies such as the anti-inflammatory devil’s claw or the soothing willow bark. Arnica and corresponding preparations from homeopathy help with more severe pain. In the case of edema, the affected area should be cooled and elevated. Sometimes compression stockings also help, which should be custom-made if possible and worn consistently. Herbal extracts from red vine leaves or horse chestnut seeds support the reduction of water retention. So do aescrin, rutoside and butcher’s broom root.
