Cleidocranial dysplasia is a rare congenital autosomal inherited skeletal disorder. Clinical manifestations represent primarily problems in the development of facial and cranial bones, as well as partial development or complete absence of the clavicles. Problems also arise on the number and eruption of teeth. The hereditary transmission of the syndrome has been reported many years ago; however the aetiology and pathogenesis of the syndrome remained unknown for many decades. Genetic studies of individuals from families bearing the syndrome correlated with experimental studies on transgenic mice gave new data regarding the syndrome’s clinical manifestations and type of hereditary transmission.
The transcription factor RUNX2 proved to have regulatory effects for both normal intramembranous and endochondral bone growth but also in dental development. Sixteen different types of mutations on various areas of the RUNX2 gene were detected and were correlated with the different clinical manifestations of cleidocranial dysplasia. Specific areas and sequences that are implicated in the appearance of mild clinical characteristics to severe skeletal manifestations accompanied with individualized dental anomalies were mapped in great detail. The deficiency of the transcription factor RUNX2 in cleidocranial dysplasia leads to deregulation of the morphogenetic mechanisms in skeletal and dental development and growth.