What are the genetic changes related to antiphospholipid syndrome ?
The genetic cause of antiphospholipid syndrome is unknown. This condition is associated with the presence of three abnormal immune proteins (antibodies) in the blood: lupus anticoagulant, anticardiolipin, and anti-B2 glycoprotein I. Antibodies normally bind to specific foreign particles and germs, marking them for destruction, but the antibodies in antiphospholipid syndrome attack normal human proteins. When these antibodies attach (bind) to proteins, the proteins change shape and bind to other molecules and receptors on the surface of cells. Binding to cells, particularly immune cells, turns on (activates) the blood clotting pathway and other immune responses.  The production of lupus anticoagulant, anticardiolipin, and anti-B2 glycoprotein I may coincide with exposure to foreign invaders, such as viruses and bacteria, that are similar to normal human proteins. Exposure to these foreign invaders may cause the body to produce antibodies to fight the infection, but because the invaders are so similar to the body's own proteins, the antibodies also attack the human proteins. Similar triggers may occur during pregnancy when a woman's physiology, particularly her immune system, adapts to accommodate the developing fetus. These changes during pregnancy may explain the high rate of affected females.  Certain genetic variations (polymorphisms) in a few genes have been found in people with antiphospholipid syndrome and may predispose individuals to produce the specific antibodies known to contribute to the formation of thromboses. However, the contribution of these genetic changes to the development of the condition is unclear.  People who test positive for all three antibodies but have not had a thrombosis or recurrent miscarriages are said to be antiphospholipid carriers. These individuals are at greater risk of developing a thrombosis than is the general population.