Abnormalities of thrombophilia tests were present in 23 patients (80%): 20 (87%) had a protein S deficiency, 3 (13%) hyperhomocysteinemia, 1 (4%) resistance to activated protein C, 1 (4%) heterozygous mutation of Factor V, 1 (4%) mutation of factor II, 1 (4%) anti-phospholipid and anti-cardiolipin antibodies and one (4%) isolated anti-cardiolipin antibodies. This evidence concerns the gene PROS1 and hyperhomocysteinemia.