RUNX2 and cleidocranial dysplasia 1: Runx2 (runt-related transcription factor 2, also known as core binding factor alpha 1 (Cbfa1), osteoblast specific transcription factor 2 (Osf2) and acute myeloid leukemia 3 protein (AML3)) is a bone restricted transcription factor essential for osteoblast differentiation and bone formation, which was validated by many researches decades ago, and mutations in Runx2 are found in 65%–80% of individuals with cleidocranial dysplasia [46,47].