PDGFD and orofacial cleft: In contrast to the above genes,FRAS1 and several members of the platelet-derived growth factor (PDGF) gene family are known to be implicated in orofacial clefts.PDGFD is a member of the PDGF gene family and plays a central role in the PDFG receptor-alpha (PDGFR-α) signaling pathway.