Fgfr1 conditional-knockout in neural crest cells induces heterotopic chondrogenesis and osteogenesis in mouse frontal bones

Most facial bones, including frontal bones, are derived from neural crest cells through intramembranous ossification. Fibroblast growth factor receptor 1 (Fgfr1) plays a pivotal role in craniofacial bone development, and loss of Fgfr1 leads to cleft palate and facial cleft defects in newborn mice. However, the potential role of the Fgfr1 gene in neural crest cell-mediated craniofacial development remains unclear. To investigate the role of Fgfr1 in neural crest cells, we analyzed Wnt1-Cre;Fgfr1^flox/flox mice. Our results show that specific knockout of Fgfr1 in neural crest cells induced heterotopic chondrogenesis and osteogenesis at the interface of the anterior portions of frontal bones. We observed that heterotopic bone formation continued through postnatal day 28, whereas heterotopic chondrogenesis lasted only through the embryonic period. In summary, our results indicate that loss of Fgfr1 in neural crest cells leads to heterotopic chondrogenesis and osteogenesis.