Furthermore, little is known about whether the aberrant expression of cAMP/PKA, Wnt/β-Catenin, MAPK, PI3K/AKT, JAK/STAT, and TGF-β/SMAD signaling pathways leads to IUGR by affecting other biological behaviors of trophoblasts, as the etiologies of IUGR are diverse. The gene discussed is TGFB1; the disease is fetal growth restriction.