Antiphospholipid syndrome (APS) is an autoimmune disorder with various symptoms including blood clots, miscarriage, rash, chronic headaches, dementia, seizures and so forth. APS occurs when your body's immune system generates antibodies that attack phospholipids. Phospholipids are a type of fat found in all living cells, including blood cells and the lining of blood vessels. A widely accepted explanation for occurrence of APS is that the disease is caused by a combination of gene mutations and an environmental exposure (such as to a virus). Most cases of APS occur in people with no family history of this disorder, however there are rare cases of APS clustering in a family.
The first official classification criteria for anti-phospholipid syndrome (APS) were drafted in 1998 at a workshop at the 8th International Symposium on Antiphospholipid Antibodies in Sapporo, Japan (Sapporo criteria). According to these criteria, APS can be considered proven if at least one clinical and one serological criterion are met. When the criteria were updated in 2004 (Miyakis criteria) antibodies against β2 glycoprotein 1 were added. Fulfilment of the criteria now encompasses at least one of the following three parameters: antibodies against cardiolipin (ACA; IgG or IgM) or β2 glycoprotein 1 (anti-2GP1; IgG or IgM) or a positive lupus anticoagulant (LA) test.