Complement C3 and C4 serum levels were assessed in several cohorts of pregnant patients with APS and/or aPL, these studies have yielded inconsistent results, while some studies have come to find a correlatio, other studies have not revealed a prognostic role for the complement in relation to pregnancy morbidity among aPL-positive women [38–40]. The gene discussed is C4A; the disease is autoimmune polyendocrinopathy.