Runx2 regulated it, at least partly, through the regulation of Fgfr2 and Fgfr3. Since Fgf signaling enhances the ability of Runx2 for transcriptional activation, the reciprocal regulation of Runx2 and Fgf signaling will play important roles in skeletal development, the pathogenesis of craniosynostosis, and the progression of some breast cancers. The gene discussed is FGFR3; the disease is craniosynostosis.