PROJECT SUMMARY It is generally accepted that there is a link between a woman’s reproductive and overall health. Following menopause, women are at an increased risk for developing diseases including cardiovascular disease, cancer, bone loss, cognitive disorders, and genitourinary dysfunction. Some diseases, such as polycystic ovary syndrome (PCOS), demonstrate a direct link between reproductive and overall health through the presence of both reproductive and non-reproductive phenotypes, including increased risk for infertility, obesity, diabetes, and cardiovascular disease. The relationship between ovarian dysfunction and non-reproductive disease in PCOS is complex - in part due to the altered hormonal environment related to pathologic ovarian follicle development. Much of the disease has been attributed to excess androgen production, but some studies indicate that the higher circulating levels of anti-Mullerian hormone (AMH) and inhibin B produced from the overabundant small ovarian follicles may also contribute to PCOS. However, the cause-and-effect relationship between reproductive and non-reproductive PCOS phenotypes is not fully understood. We have designed this exploratory R21 study to fill this knowledge gap based on a newly discovered SMAD variant in a PCOS patient and her PCOS daughter identified through the NIH-funded Rare and Atypical Diabetes Network (RADIANT) at Baylor College of Medicine. These clinical and genomic data provide us the unique opportunity to analyze the role of altered TGFβ superfamily signaling in driving ovarian defects and dysregulating metabolism. Structural studies and preliminary data indicate that this rare variant is damaging and thus supports a hypothesis that altered TGFβ superfamily member signaling has the potential to play a causal role in a subset of PCOS. These studies leverage our published expertise in SMAD signaling and mouse models alongside cutting-edge proteomic analysis and comprehensive phenotyping resources developed by the NIH-funded Knockout Mouse Phenotyping (KOMP) Program at Baylor College of Medicine. Our two aims propose a broad biochemical analysis to determine how this variant alters canonical and noncanonical SMAD properties, and identify the causal underpinnings of reproductive and non-reproductive disease phenotypes in PCOS that emerge from defective SMAD signaling. Thus, by studying this variant, we can uncover new mechanisms leading to PCOS outcomes as well as uncover novel links between infertility and overall health, both of which may serve to broaden the range of pathways for therapeutic targeting.