PITX2 and omphalocele: In this context, it should be noted that mice deficient of Pitx2, which is expressed in left somatic mesodermal cells at the early stage of E8.0-E9.0 (Campione et al., 1999), show severe ventral body wall closure defects including omphalocele (Kitamura et al., 1999; Gage et al., 1999; Eng et al., 2012).