Since an ectopic condensed mesenchymal cell mass was observed in the posterior domain of each palatal shelf of E13.5 transgenic embryo (Fig. 2D) where ectopic pSmad1/5/8, P-p38, and P-JNK positive cells and expression of Shox2 and Msx1 were detected (Fig. 4; 5), we wondered if this condensed cell mass represents a condensation of precartilagious cells and the formation of ectopic cartilage within the palatal shelves could contribute to deformed palate morphology and subsequently to the cleft palate defect. This evidence concerns the gene MSX1 and cleft palate.