Cleidocranial dysplasia is a rare condition characterized by abnormalities in the bone development of the skull and collarbones. Patients with this condition have greatly reduced or entirely absent collarbones, and their skulls also suffer from a lack of bone density. In addition to being passed genetically through families, cleidocranial dysplasia can also appear as a spontaneous mutation. Although people with this condition may experience some physical developmental delays, their intellectual development is usually normal.
One of the signatures of this condition is incomplete or very slow closure of the sutures in the skull. The skull is made up of a series of bones which gradually fuse together as people grow up, allowing the brain room to grow. In people with cleidocranial dysplasia, the skull fails to fuse as expected. Patients may be prone to hearing loss and ear and sinus infections, and it is not uncommon for the eyes to be unusually widely spaced.
Many patients also experience dental problems. Teeth may fail to erupt on schedule, while supernumerary teeth may appear at random in the mouth. Orthodontic work can address many of the dental problems, promoting even development of healthy teeth and keeping the patient's mouth in good shape. The lack of collarbones in some patients can allow them to touch their shoulders together in front of the body, and in patients with some presence of collarbones, the shoulders are still unusually mobile.
Complications of cleidocranial dysplasia can include short stature, scoliosis, and narrowing of the pelvis. It is also not uncommon for patients to experience a loss of bone density all over the body, which puts them at risk for fractures, especially as they age. Bone health needs to be nutritionally supported to decrease the frequency of fractures.
This condition is caused by an error in a gene on the sixth chromosome. Parents cannot prevent it; if they carry the gene, they put their children at risk of developing in the condition, and no actions undertaken or avoided during pregnancy will reduce the risk of cleidocranial dysplasia. If the condition occurs as a spontaneous mutation when neither parents carry the gene, it is a random occurrence which could not have been controlled. Parents who are concerned about passing the gene on to their children can consider using assisted reproductive technology to increase their chances of having children who do not carry the gene. Parents should also be aware that the gene manifests in different ways in different people, even in the same family, which means that the symptoms and severity of cleidocranial dysplasia can be quite variable.