RUNX2 and cleidocranial dysplasia 1: Cleidocranial dysplasia, also known as Marie and Sainton disease [5] or cleidocranial dysostosis [1], is associated with a spontaneous mutation in the gene encoding for transcription factor core binding factor alpha 1 (Cbfa1), which is essential for osteoblast and odontoblast differentiation as well as for bone and tooth formation [6].