Cleidocranial dysplasia is a rare birth condition most notable for the lack of collarbones (or small collarbones- clavicles). While this is recognizable, other findings include abnormalities of the teeth as well as delaying closing of the fontanelles (skull bone deficits). This is an autosomal dominant condition related to the RUNX2 gene but importantly, it is often the result of a new mutation. More information on the gene can be found HERE. Genetic testing can help the diagnosis of cleidocranial dysplasia but may not be necessary. The identified gene is also known as the CBFA1 gene located on the short arm of chromosome 6.
A few other sites provide good summaries of cleidocranial dysplasia including the rarediseases site through the NIH, the NORD site, and OMIM.
From an orthopedic surgeon standpoint, the lack of the clavicle or collarbones is the most notable and unusual finding. This provides dramatic shoulder mobility but does not specifically cause problems with daily function. Therefore, surgery or other intervention is not required. And this is different than pseudoarthrosis of the clavicle– a condition on only one side (vs both sides with cleidocranial dysplasia) and one that may benefit from surgery. I have previously blogged on it HERE.
The images of a patient with cleidocranial dysplasia without clavicles are dramatic- demonstrating the mobility of the shoulders seen below.
|Patient with Cleidocranial dysplasia which is not immediately noticeable.|
|Patient with Cleidocranial dysplasia showing dramatic flexibility.|
|Patient with Cleidocranial dysplasia.|
|Patient with Cleidocranial dysplasia without obvious difference from behind.|
|Cleidocranial dysplasia x-ray demonstrating absent clavicles|