TGFB1 and hypothyroidism: Thus, TGF-β and Treg level reduction may favour autoimmune processes and it can be speculated that women with PCOS carrying allele 8 of D19S884 in the FBN3 gene who have lower levels of TGF-β1, are more susceptible to developing hypothyroidism than women with PCOS without allele 8 (10, 73).