Cleidocranial dysplasia is a bony autosomal dominant disorder, defined by late closure of fontanels and sutures, clavicular aplasia or hypoplasia and supernumerary teeth. The aim of our study was to define the CBFA1 mutations in three families with cleidocranial dysplasia and to describe the phenotype expression within and between the families. While the mutation R225Q caused a similar phenotype within one family, the mutation G146R, located in the same domain, was the cause of a variable expression between two family members. A third mutation, R190Q was responsible for symptoms not commonly associated
with this disorder. The results of our craniofacial examination are in agreement with the numerous descriptions in the literature. This study accents the difficulty in establishing a clinical based diagnosis due to the wide variability.