This is supported by the identification of significantly reduced levels of VD, (VDBP) and VDR in UI females and a mutation in the VDBP gene at the rs 4588 SNP in exon 11 that affected the protein function (Thr 436 Lys). Furthermore, enrichment of the plasma membrane estrogen receptor signaling pathway in VD-deficient infertile females, especially VDR, SMAD3, NCOR1, CREBBP, NCOA1, STAT1, GRB2, PPP2CA, TP53, and NCOA2 directs towards a link of infertility with VDD. This evidence concerns the gene SMAD3 and Infertility.