The classification criteria for definite APS need at least one of the clinical criteria: (1) Vascular thrombosis, (2) Pregnancy morbidity; and laboratory criteria: (1) LA is positive more than two at least 12 weeks apart, (2) Anticardiolipin (aCL) antibody of IgG and/or IgM isotype are positive in medium or high titer on more than two at least 12 weeks apart, (3) Anti-β2 glycoprotein-I antibody of IgG and/or IgM isotype are positive in medium or high titer on more than two at least 12 weeks apart [5]. This evidence concerns the gene CD40LG and deep vein thrombosis.