RAB5B, PCOS GWAS candidate, is a Rab-GTPase, also thought to be involved in endocytosis and receptor recycling and could, therefore, be a molecule interacting with the DENN domain (20,21,22) and has also been reported to involve PI3K, PKB, and MAPK/ERK components (23). Here, RAB5B is linked to polycystic ovary syndrome.