FBN3 and polycystic ovary syndrome: Among them, the FBN3 gene variants seem to be the most plausible candidates due to their influence on TGFβ activity, and consequently, on the level of Tregs. After all, the role of TGFβ has already been implicated in the pathogenesis of PCOS and HT. Additionally, vitamin D deficiency was shown to decrease Tregs.