Abstract
Family studies have shown that polycystic ovary syndrome (PCOS) has probable genetic transmission because of a high incidence of relatives who present clinical or biochemical characters of the syndrome. However, initial candidate gene studies were unsuccessful. Genome wide association studies (GWASs) have shown that at least 29 gene alterations are common in PCOS, but it has been calculated that the altered genes found by GWASs may represent only 10% of affected patients. Rare altered uncoding genes may explain the syndrome in an additional group of patients. In many other patients, the altered genes found by GWASs may represent a risk condition for the development of the syndrome, and new candidate gene studies have shown that some gene alterations that mainly concern androgen production may be common in PCOS. Finally, in most patients, epigenetic and environmental factors may be necessary to transform a risk condition into this common and important syndrome.