As a result, anti-C9 antibody was detected in 2 of 13 specimens from SN-APS patients without known thrombophilia (no.15, No.16), and in 1 of 13 specimens of SN-APS patients with thrombophilia (No. 4); no band was detected in the four control samples (Fig 5). Here, C9 is linked to Rare hereditary thrombophilia.