Patients with a clinical history suggestive of APS, such as those with recurrent arterial venous thrombotic events, recurrent miscarriages, or unexplained thrombocytopenia, who have persistently negative aPL test results on at least two occasions, and who have had other causes of thrombosis ruled out, should be suspected of having seronegative APS, which is a diagnosis of exclusion [9]. This evidence concerns the gene FASLG and autoimmune polyendocrinopathy.