C4A and autoimmune polyendocrinopathy: Having positive ANA 81% vs. 60%; p = 0.006), low levels of C4 (29% vs. 14%; p = 0.042), and an isolated aCL as aPL profile at APS diagnosis (35% vs. 17%; p = 0.013) were the most frequent laboratory findings in the group without valvular involvement.