TNF and polycystic ovary syndrome: However, a methionine 196 arginine polymorphism in exon 6 of the gene encoding the TNF-α receptor 2 was reported to be significantly more frequent in women with PCOS than in controls, suggesting that TNF-α plays a role in the development of metabolic pathologies in PCOS and that this might be related to a structural change in the TNF-α receptor that confers a more responsive phenotype, rather than to circulating TNF-α levels or to the density of TNF-α receptors per se [130].