Palatogenesis and Palatoschisis. A Review on the Cellular and Molecular Mechanisms of Development

The formation of the palate is a highly complex developmental process beginning with the growth of facial primordia and the subsequent fusion of the nasal and maxillary prominences, thus giving rise to the primary palate and upper lip.Development of the secondary palate occurs through the union of bilateral palatal shelves arising from the maxillary prominences that fuse with each other on the midline, thus leading to a continuous palate that definitively separates the oral and nasal cavities.If the intricate process underlying craniofacial morphogenesis is disrupted, an orofacial cleft may occur.The cellular and molecular bases of palate shelf fusion have not yet been clearly elucidated.Therefore, this review focuses mainly on the recent advances in knowledge about secondary palatogenesis, with special attention to the cellular and molecular mechanisms involved in the fusion of the apposing shelves as well as their failure to properly take place, thus generating clefting.