RUNX2 and cleidocranial dysplasia 1: Runt-related transcription factor 2 (RUNX2) is a key transcription factor controlling skeletal development and morphogenesis in vertebrates.11–13 Recent studies have demonstrated that RUNX2 haploinsufficiency results in cleidocranial dysplasia (CCD) in humans and mice, which is characterized by incomplete fontanelle closure, hypoplastic clavicles, short stature, and skeletal dysplasia.12 Consequently, regulating RUNX2 expression and transcriptional activity is critical for osteoblast differentiation and normal bone formation.