Cleidocranial dysplasia is a condition usually characterized by the absence or underdevelopment of the clavicles and a wide opening of the fontanelles and cranial sutures. Other bones of the body may also be deformed. In addition, dental changes may occur as part of the disease. Cleidocranial dysplasia is inherited and occurs very rarely.
What is cleidocranial dysplasia?
Cleidocranial dysplasia is characterized by a malformation of connective tissue-like or of cartilaginous preformed bones. The clavicles, pelvis, and skull are primarily affected by the malformations. The disease has a frequency of 1:1,000,000 and thus occurs extremely rarely. Cleidocranial dysplasia is a hereditary disease in which inheritance is usually autosomal dominant. However, a recessively inherited form also exists. Cleidocranial dysplasia is classified as a disease with congenital malformations of the upper extremities as well as the shoulder girdle.
Causes
Because cleidocranial dysplasia is an inherited disease, the main cause is a genetic defect. The disease is primarily caused by mutations in a specific gene called the RUNX2 or CBFA1 gene. The genetic defect responsible for cleidocranial dysplasia is inherited in an autosomal dominant manner. However, in an average of one in three patients with the disease, it is a spontaneous mutation that has newly arisen. The gene responsible for the disease, RUNX2/CBFA1, has the function of differentiating osteoblast progenitor cells. The gene is also responsible for differentiation of chondrocytes, which are relevant in relation to enchondral bone formation. As a result, there is decreased enchondral bone formation as well as decreased desmal bone formation in the setting of cleidocranial dysplasia.
Symptoms, complaints, and signs
In the context of cleidocranial dysplasia, various symptoms and complaints may occur, primarily resulting from the malformations of the affected bones. Therefore, symptoms vary depending on the clinical picture, localization of the malformations, as well as the severity of cleidocranial dysplasia. The disease is characterized, for example, by a short stature of the affected individuals, although this fact only becomes apparent in adulthood or after completion of the growth phase. Female patients have an average height of 149 centimeters, while male patients have an average height of 170 centimeters. Cleidocranial dysplasia is also associated with other symptoms. The condition can manifest itself, for example, in the fact that affected individuals are able to bring their shoulders unusually close together. In individual cases, it is even possible for the shoulders to touch. In addition, affected patients have a relatively narrow thorax. This is also characterized by a bell-like shape. The shoulder blades may also protrude like wings. Certain malformations in cleidocranial dysplasia can cause a narrow pelvis. Changes are also possible in the hands and feet of affected patients.
Diagnosis and course
The diagnosis of cleidocranial dysplasia results primarily from the obvious, clinical symptoms of the disease in the form of malformations of the bones. These are reliably diagnosed by typical changes that can be detected by X-ray examination. For example, affected individuals have a short and unusually broad head (medical term brachycephaly). Abnormalities are also seen in the cranium, which is particularly large. At the same time, the facial skull tends to be smaller. The patient’s face also shows peculiarities that are due to cleidocranial dysplasia. For example, the distance between both eyes is increased and the fontanelle in the anterior part of the skull is not closed. Patients show delays in ossification of the skull, and the fontanelles may remain very wide open into adulthood. The X-ray also shows that there are changes in the area of the femoral necks and pelvis in the form of malformations of the bones.In addition, the diagnosis of cleidocranial dysplasia can be confirmed by molecular genetic testing. If evidence of a mutation of the RUNX2 or CBFA1 gene is obtained, the diagnosis can be made with certainty.
Complications
In most cases, cleidocranial dysplasia results in various deformities of the bones in the patient’s body. Likewise, there are deformities and changes in the teeth, which puts a strain on the daily life of the affected person. As a rule, all complaints and complications in this disease arise from the malformations of the bones. Therefore, they strongly depend on the particular malformation. In many cases there is a reduced height, which can only be diagnosed at a young age. A short stature can thus not be detected directly in childhood. Often there are also malformations of the shoulders, so that they even touch each other in patients. Changes also occur in the pelvis, hands and feet. In the worst case, these can also lead to restricted movement. The patient may then be dependent on the help of other people in everyday life. As a rule, no causal treatment of the disease is possible. Treatment is therefore based primarily on the symptoms and deformities. In many cases, these can be surgically corrected so that the patient does not suffer any limitations. Life expectancy is not reduced by the disease. The development of intelligence is also not affected.
When should one go to the doctor?
Cleidocranial dysplasia is usually diagnosed immediately after birth and treated directly, if possible. Whether further visits to the doctor are necessary depends primarily on the severity of the malformations. For example, malocclusions of the teeth and changes in the pelvis must always be clarified and treated by a doctor. Parents who notice movement restrictions or other symptoms in their child that indicate a serious condition should talk to the pediatrician. He or she will perform a comprehensive physical examination and then refer the parents to an appropriate specialist. In addition, a physician should be consulted if additional complaints arise later in life or if the child suffers psychologically from the existing deformities. In the case of psychological problems such as inferiority complexes or depression, it is best to speak directly with a therapist. Sometimes, those affected are also dependent on support in everyday life. This should be arranged as early as possible, preferably immediately after the diagnosis of cleidocranial dysplasia.
Treatment and therapy
With regard to the treatment of cleidocranial dysplasia, various methods are available based on the severity of the malformations. In the case of malformations of the shoulder girdle, the affected patients have little to no restrictions in their daily lives in most cases. Therefore, no therapy is necessary in this case. In the treatment of dental deformities, which may also be related to cleidocranial dysplasia, these are treated by dentistry or orthodontics. Here, the goal is to obtain a functionally and aesthetically satisfactory result. Therefore, missing, supernumerary as well as abnormal teeth of the affected person are removed. In addition, bone density should be checked regularly to counteract possible osteoporosis.
Outlook and prognosis
The prognosis of cleidocranial dysplasia is generally good. In only very rare cases is there impairment of the skeletal system that cannot be corrected. The prospect of health improvement is tied to the intensity of the existing deformities. Individual complaints as well as manifestations of the complaints occur in each patient. These must be taken into account when making a prognosis. The cause of the genetic disease cannot be cured. Nevertheless, most symptoms and malformations can be treated by the available medical possibilities. Corrections of the teeth or bones are made. These represent an immense improvement in the quality of life and remain for life. Only an occurring short stature of the patient cannot be treated or corrected. Patients suffering from reduced physical size have the worst prognosis in cleidocranial dysplasia. Here, the risk of mental disorder is increased.Behavioral disturbances may occur or self-confidence is lowered. Nevertheless, the patient does not suffer from physical complaints such as pain or the like. In addition, life expectancy is in no way affected. However, if a mental illness occurs, the patient’s well-being deteriorates considerably. A cure often takes several years and can have consequences for all areas of life.
Prevention
Because cleidocranial dysplasia is an inherited disease, there are no options for prevention. The only option is to treat the symptoms of cleidocranial dysplasia and thereby positively affect the quality of life of those affected.
Follow-up
As a rule, there are no special aftercare options available to the affected person with this condition, since the disease cannot be treated causally, but only symptomatically. Since it is a hereditary disease, the patient’s parents and the patient himself should participate in genetic counseling if he wishes to have children, in order to possibly avoid inheriting the disease. As a rule, the malformations are treated by surgical interventions, the procedures being based on the type and severity of the malformations. After such an operation, the affected person needs a lot of rest and must give the body both recovery. If the disease also affects the oral cavity and leads to malformations or deformities of the teeth, these must also be removed. In this case, regular check-ups by a dentist are advisable in order to avoid further complications and complaints of the teeth. The bone density of the patient should also be checked regularly. Since the disease also has a very negative effect on the self-confidence of the affected person, psychological counseling can be useful in order to avoid depression and other psychological upsets. The parents of the affected person can also participate in this.
What you can do yourself
Cleidocranial dysplasia is an inherited disorder. There is currently no way to treat the disorder causally. Instead, attempts are being made to treat the symptoms in order to improve the quality of life of those affected. Most of the symptoms caused by the disease result from malformations of the bones. Whether and what the patient himself can do to improve his condition depends on the type of malformation. If the ability to move is very severely restricted, patients should familiarize themselves at an early stage with the functioning of the various walking aids on offer. The correct handling of these aids should be learned at an early stage. A (power) wheelchair as well as vehicles specially equipped for the walking impaired can also help maintain mobility. In the case of changes in the hands that make it difficult to grasp and write, physiotherapeutic exercises very often help to regain or improve the ability to move. Cleidocranial dysplasia is also often accompanied by changes in the teeth. These are often abnormally large or small, and frequently the teeth also show severe malocclusion. This is not only very disfiguring, but can also make it difficult to eat. Affected individuals should consult an experienced dentist and, if necessary, an orthodontist in these cases.
