TGFB1 and Microglossia: For example, mesenchymal-specific deletion of the TGFBR2 gene in TGFβ signaling and loss of KiF3a and intraflagellar proteins in Shh signaling lead to microglossia (Hosokawa et al., 2010; Iwata et al., 2013; Parada et al., 2012) and aglossia (Millington et al., 2017), respectively.