The prenatal frontal and parietal bones are distinct organs.
The skull vault is composed of frontal and parietal bones that are connected by flexible sutures that protect the growing brain. Intramembranous ossification in the prenatal skull vault starts by mid-gestation in the mouse, and sutures must remain flexible for normal growth and development. Therefore, the balance of bone formation and remodeling needs to be precisely controlled because premature ossification in the sutures causes craniosynostosis (CS) to develop. CS has a variable clinical presentation where two frontal bones may be fused together, or a frontal bone may be fused to a parietal bone. While most studies focus on the premature suture ossification, we hypothesized that the process of intramembranous ossification in the frontal and parietal bones contributes to the etiology of CS. By bulk RNASeq we identified 536 unique transcripts between the frontal and parietal compartments.Taken together, we propose that the frontal bone is more active in bone remodeling than the parietal bone, and this control is important for temporal onset of intramembranous ossification in the skull vault. Overall design: To determine the transcriptomic differences between the E15.5 frontal and parietal bones