Pax9 is expressed in a posterior to anterior gradient in the palatal mesenchyme and studies on Pax9−/− mice have revealed cleft palate associated with defects in palatal growth/elevation, while expression of Bmp4, Msx1, Fgf10 and Osr2 was reduced in the palatal mesenchyme. The gene discussed is PAX9; the disease is cleft palate.