Chordin (Chrd) is a BMP antagonist that has well-characterised roles in vertebrate dorsoventral patterning. Now Bachiller et al. report that Chrd is also required for vertebrate head and neck patterning, as revealed by its inactivation in mice (see p. 3567). Surprisingly, many of the defects in Chrd-/- mice –such as those affecting the pharyngeal arches, palate, parathyroid gland and heart – are characteristic of DiGeorge syndrome (DGS), despite the fact that Chrd maps outside of the microdeletion that causes this human disease. Clues to its involvement, however, came from studies of Tbx1and Fgf8, which are implicated in the aetiology of DGS: both are downregulated in Chrd-/- pharyngeal tissue and can be induced in frog explants by Chrd mRNA. These findings thus uncover a role for Chrd in regulating Tbx1 and possibly other factors important for pharyngeal development. Whether it is involved in other human head and neck congenital abnormalities awaits further study.

© 2003.
2003