In addition, networks in the IPA analysis provide supportive evidence for genes such as NFKB, P38MAPK, Mapk, Akt, Vegf, retinoic acid, HOXA9, TNF, dihydrotestosterone, thyroid hormone, CDKNA1, sulfotransferase, Ggt, Oleic acid, progesterone, CCL2 and KNG which were not differentially expressed in our data set but could play significant roles in PTD. Here, TNF is linked to Bjornstad syndrome.