These confounding factors could be divided into 3 major groups: (1) none; (2) other concomitant autoimmune diseases, including SLE, rheumatoid arthritis (RA), and related organ injuries (such as heart injuries); and (3) APS diagnosis absolutely depended on different types of positive antibodies, which meant that the APS patients were divided into the following: (1) the single positive antibody groups, such as laC(+), aCA(+), and aβA(+); (2) double positive antibody group, such as laC/aCA(+), aCA/aβA(+), and laC/aβA(+); and (3) triple positive antibody group. The gene discussed is LCT; the disease is rheumatoid arthritis.