The Ectodysplasin and NFκB signalling pathways in odontogenesis

Hypohidrotic ectodermal dysplasia (HED) is a congenital disorder affecting organs of ectodermal origin including teeth, hair and sweat glands. Defects in Ectodysplasin (tabby), Edar (downless) and Edar associated death domain (Edaradd) (crinkled) cause HED in both humans and mice. Ectodysplasin is a tumour necrosis factor (TNF) superfamily member whose downstream signalling is transduced by the inhibitor of κB kinase (IKK) complex and inhibitors of κB (IκB) to activate the transcription factor NFκB. NFκB signalling is involved in a wide range of cellular processes and at each stage the different family members must be tightly regulated for each function. Recent data have demonstrated the importance of this signalling pathway in odontogenesis, particularly in the formation of cusps. Here we review recent advances in our understanding of Ectodysplasin/NFκB signalling in tooth development and in particular the central role of the IKK complex.