PDGFRA and Mobius syndrome: In our prior studies (Vodyanik et al., 2010), we revealed that APLNR+PDGFRα+ primitive posterior mesoderm induced from hPSCs in coculture with OP9 stromal cells acquires the potential to form FGF2-dependent compact spheroid colonies in semisolid medium with a MSC and endothelial potentials that define MBs.