Recurrent mutations, such as KRAS, PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase), PPP2R1A (Protein Phosphatase 2 Scaffold Subunit Alpha), and ARID1A (AT-Rich Interaction Domain 1A), are observed in endometriosis and adenomyosis, which suggests similar disease development. Here, ARID1A is linked to endometriosis.