Genetic overlap between polycystic ovary syndrome and bipolar disorder: the endophenotype hypothesis.

Polycystic Ovary Syndrome (PCOS) is a polygenic disorder caused by the interaction of susceptible genomic polymorphisms with environmental factors. PCOS, characterized by hyperandrogenism and menstrual abnormalities, has a higher prevalence in women with Bipolar Disorder (BD). Theories explaining this high prevalence have included the effect of PCOS itself or the effect of drugs such as Valproate, which may cause PCOS either directly or indirectly. Incidentally, metabolic abnormalities are observed in both bipolar and PCOS patients. Endophenotypes such as insulin resistance, obesity, and hyperglycemia are common among BD and PCOS patients, suggesting some degree of pathophysiological overlap. Since both BD and PCOS are complex polygenetic diseases, the endophenotype overlap may be the result of common genetic markers. This paper postulates that shared clinical endophenotypes between PCOS and BD indicate common pathophysiological platforms and will review these for the potential of genetic overlap between the two disorders.