PRB2 and autoimmune polyendocrinopathy: In addition, anti‐phosphatidylethanolamine (anti‐PE) IgG, IgM10, 11 antibodies and anti‐phosphatidylserine/prothrombin (anti‐PS/PT) antibodies,12, 13 which are termed as seronegative APS (SNAPS), are also potentially associated with RPL, despite being excluded from the Sydney classification criteria.14, 15