IRF6 and van der Woude syndrome: Individuals with mutations in either of the epithelial transcription factors grainyhead-like transcription factor 3 (GRHL3) and interferon regulatory factor 6 (IRF6), detected in families with Van der Woude syndrome (Box 1), tend to present with CLP (de Lima et al., 2009; Peyrard-Janvid et al., 2014).