1 Introduction 1. 1 Wnts and Development The f amily of Wnt genes consists of at least 19 members in vertebrates. Wnts ha v e multiple roles during normal development and aetiology of diseases (Wodarz and Nusse 1998; Moon et al. 2002, 2004). These genes encode for glycoproteins that are released in the intercellular space, acting as intercellular mediators (Moon et al. 1997). By binding to their special receptors, the Frizzled (Fz) receptors, they are able to activate at least three different pathways: the canonical, the non-canonical and the Ca 2+ pathway (Fig. 1 ). The Wnt family has been...