Bethlem myopathy is a very rare inherited disease that is associated with muscle weakness and wasting, as well as limited joint function and movement.
What is Bethlem myopathy?
Bethlem myopathy was first described in 1976 by scientists J. Bethlem and G. K. Wijngaarden. That is why it was given its name in 1988. It is a very rare disease; to date, only just under 100 cases have been documented.
Causes
The cause of Bethlem myopathy is a genetic defect. When one of the three genes responsible for collagen VI ( COL6 A1, COL6 A2, or COL6 A3) mutates, metabolism in the mitochondria does not function properly. If these energy suppliers of the muscles do not work properly, the muscle tissue is gradually transformed into connective tissue and this process is unstoppable and progressively destroys the muscles. Those who carry the genetic defect inevitably get the disease and their children inherit the genetic defect with a probability of 50 percent. Scientists refer to this as autosomal dominant inheritance. In most cases, the disease appears in the neonatal period, but sometimes it appears much later. There are also different degrees of severity and courses of the disease.
Symptoms, complaints, and signs
If the disease occurs very early, it is first recognized by delayed motor development, a general reduction in movement, and especially by restricted movement of the finger, hand, elbow, and ankle joints. Due to shortened muscles and tendons, the fingers and toes cannot be moved properly, the elbows and sometimes the knees cannot be stretched properly. In some cases, the joints are also hypermobile, can be overstretched. In addition, there is often a poor temperature balance. The affected children freeze very quickly and excessively. In the adult patient, the symptoms are similar. In addition, there is a progressive stiffening of the spine, arthrosis of the joints, rapid fatigability of the muscles. Affected persons can, for example, climb stairs only with difficulty and have difficulty stretching their arms above their heads. Wounds heal poorly, scars appear bulging, and digestive problems may occur. In many cases, adult patients also have impaired lung function because tendon shortening may occur in the spine around the upper body. Often the skin condition is also poor. Not all sufferers experience the same symptoms. In some, the movement restrictions are more pronounced; in others, muscle weakness is the bigger problem.
Diagnosis and progression
Diagnosis of Bethlem myopathy is very difficult because the symptoms apply to many different conditions and the disease is so rare. There are many affected individuals in whom it takes years to find the true cause of their condition. However, family history should give good clues, precisely because Bethlem myopathy is a hereditary disease and runs in families. Imaging techniques such as X-ray, MRI, and electromyography cannot give a definitive result. Even a muscle biopsy only works to a limited extent. Only a genetic test can provide final certainty of the gene defect. With increasing age, the disease becomes more and more noticeable, also because various secondary diseases occur.
Complications
Various complications occur with Bethlem myopathy, but in most cases they affect the muscles. Joints may also be affected by Bethlem myopathy. The disease may appear in childhood or only in adulthood. It is not possible to predict the onset of Bethlem myopathy. In young children, Bethlem myopathy severely limits all movements. This includes especially the movements of the fingers and the joints. The patient’s daily life is severely limited and the quality of life decreases. In children, Bethlem myopathy can lead to bullying, which can result in depression and suicidal thoughts. In some cases, patients rely on the help of strangers to cope with daily life. Adults suffer from similar symptoms, but muscles become tired even more quickly. Climbing stairs is hardly possible anymore, so that severe restrictions in movement occur in this case. Bethlem’s myopathy results in slowed healing of wounds. This can lead to infections and inflammations.The lungs are also affected by these inflammations. The skin of those affected is unclean, there are often pimples and redness associated with itching. Treatment is possible only through physiotherapy, which does not lead to a positive course of the disease in every case.
When should you go to the doctor?
Bethlem myopathy can be recognized by some clear symptoms. If there is limited movement in the joints of the fingers, hands, elbows, and feet, this should be evaluated by a physician. Parents who notice delayed motor development or a general reduction in movement in their child should consult the pediatrician. An immediate visit to the doctor is necessary if severe movement restrictions occur in the fingers and toes. In adults, progressive stiffening of the spine and rapid fatigability of the muscles indicate Bethlem’s myopathy or other disease that must be evaluated and treated immediately. In addition, wound healing is disturbed and disturbances of the pulmonary and digestive tracts occur. In particular, if there are hereditary diseases in the family, the symptoms mentioned should be taken to the doctor quickly. A genetic test provides information about the causative disease and enables comprehensive therapy. If the disease remains untreated, the symptoms increase in intensity over the course of life and eventually lead to a severe decrease in quality of life.
Treatment and therapy
To date, there is no cure for Bethlem myopathy. Medications for the underlying condition are not available, and surgical interventions are also not promising because of the progression of the disorders and are therefore performed only in exceptional cases. However, those affected can do a number of things to alleviate the symptoms associated with the disease and to delay complications and deterioration. Stretching exercises, for example, are helpful in keeping the muscles as supple as possible and preventing tension. Warmth and a good balance between activity and rest are also good. Overweight people should try to reach a normal weight. This is also good for the muscles and joints. Weight training and excessive stress on the muscles should be avoided at all costs. On the other hand, it is important that patients do everything possible to remain active and mobile for as long as possible. Special physiotherapeutic and occupational therapy measures have a positive effect. Sports that are easy on the joints and muscles include swimming, light water gymnastics, bicycle ergometers and treadmills, as long as patients can still do them. Of course, they must still avoid falling or overloading the joints. If the disease is advanced, patients will then need aids to help them cope with everyday life. These can be orthoses that support affected limbs, walking aids, rollators, bath lifts, toilet seat raisers or wheelchairs. There are also various smaller practical aids that are helpful in everyday life. The assortment ranges from gripping aids, special knives and scissors to shoe and stocking tighteners and special cutlery. In extreme cases, affected patients may even need to be ventilated if the respiratory muscles are particularly severely affected.
Outlook and prognosis
Bethlem myopathy has an unfavorable prognostic outlook. The cause of the disease is an irreparable genetic defect that is not curable with the latest scientific and medical methods. In addition, for legal reasons, intervention and thus alteration of human genetics is not permitted. The disease has a progressive course in which the symptoms gradually spread unabated over several years. In the final phase, the affected person is no longer able to manage his or her own daily life without adequate assistance. The patient receives medical and therapeutic support to alleviate the accompanying symptoms so that he or she can achieve the best possible quality of life despite the disease. However, there is no recovery with Bethlem myopathy so far. Successful efforts are made in delaying the progressive course. Targeted training and exercise sessions are used to maintain the muscles. Stretching and training on how to perform optimal movements despite the limitations are emphasized.The patient can perform many learned training units independently in everyday life and also receives medically trained support that adapts to the ever-changing individual circumstances. Through sports activities and a healthy lifestyle, the affected person increases his well-being. In addition, when taking advantage of psychotherapeutic support, he can optimally cope with the processing of challenges in everyday life.
Prevention
There are no preventive measures for Bethlem myopathy. However, it is important to recognize the hereditary disease as soon as possible and to provide affected individuals with the best possible care. If possible, they need comprehensive interdisciplinary medical care right from the start, with neurologists, orthopedists, pulmonologists and specialists in internal medicine working together. However, psychosocial counseling is equally important. Self-help groups are also highly recommended. The better sufferers know about the disease, the better they can cope with it and the higher their quality of life will be.
Here’s what you can do yourself
Bethlem myopathy shows different courses in terms of severity and progression of symptoms. Because the autosomal-dominant inherited disease is extremely rare, the first symptoms are often misinterpreted and assigned to another disease. If symptoms occur in early childhood, they are usually motor development disorders and movement restrictions. Adaptive behavior in everyday life can be important for the further course of the disease. Since no therapies are known so far that could stop or even cure Bethlem myopathy, psychosocial care is important. Therefore, the connection to a self-help group is important. Those affected can exchange ideas and receive care from each other. Muscular stretching exercises are recommended, which should be supervised by a physiotherapist, but which the sufferers can also do themselves. The main goal is to maintain the functionality of the muscles and the mobility of the joints as long as possible. In the course of the disease, muscle cells are increasingly replaced by connective tissue cells, so that the muscles lose elasticity and strength. Recommended sports include swimming, light aqua aerobics and bicycle ergometers. Excessive strain on the muscles and joints should be avoided. As the disease progresses, self-help also consists of setting up technical aids within the home. These can be, for example, entry aids for the bathtub, stair lifts, toilet seat raisers and many other practical precautions that are individually adapted to the sick person.
