Mice lacking IGF-beta 3 exhibit an incompletely penetrant failure of t
he palatal shelves to fuse leading to cleft palate. The defect appears
to result from impaired adhesion of the apposing medial edge epitheli
a of the palatal shelves and subsequent elimination of the mid-line ep
ithelial seam. No craniofacial abnormalities were observed. This resul
t demonstrates that TGF-beta 3 affects palatal shelf fusion by an intr
insic, primary mechanism rather than by effects secondary to craniofac
ial defects.