Antiphospholipid syndrome (or APS) is an auto immune disorder in which the patient´s body makes antibodies, called Antiphospholipid antibodies, which cause the blood to become "thickened and sticky". Normally, antibodies (proteins made by the body´s immune cells to stick to foreign "invaders") are manufactured by the body to help fight off bacteria or viruses, but in the Antiphospholipid Syndrome, abnormal antibodies are made for reasons not yet fully understood. Because these antibodies target blood vessels in the patients own body instead of an obvious "invader" it is called "autoimmune" meaning the antibody attacks the patients own body. These "rogue" antibodies stop the blood flowing normally in the blood vessels and affect the delivery of oxygen to vital tissues and organs. The disorder can uniquely affect both veins and arteries and can lead to a long list of symptoms.

The disorder, first described in 1983, is now recognized as a major thrombotic syndrome, with clinical implications in almost all aspects of medicine. There are many ways in which this disorder can affect the body. APS is linked to an increased risk of vein thrombosis, including blood clots in the legs such as deep vein thrombosis (DVT). APS may be to blame in some cases of economy class syndrome, which has led to the deaths of young people travelling on long-haul flights. It is also attributed to dangerous arterial thrombosis, strokes and heart attacks. Other features of the disorder range through deep vein thrombosis, chronic leg ulcers, recurrent miscarriages, headaches, migraines, heart attacks, renal vein and artery thrombosis, to lung clots and hypertension. The major organ that is more frequently under attack is the brain. Since the initial description of stroke as a feature of APS, it has become recognized that the syndrome is an important cause of neurological problems. A number of studies have recognized that up to one in 5 of "young" strokes (aged 45 or under) are associated with the syndrome - a finding of 1 in 5 of almost every condition associated with clotting can be viewed as a conservative estimate of the number of people affected by APS - the enormous clinical and socio-economic impact is self-evident.

Sometimes, the effects of clotting are not as immediate or life threatening as in a stroke or heart attack; and the condition can creep into the lives of sufferers over a long period of time. Due to the variety of ways APS can present itself, it can be many years before a correct diagnosis is made.

Many people have a history of headaches and migraines, often going back to their teens. The headaches can be severe and frequent and sometimes associated with speech disturbance. Memory loss is a major feature in many APS patients - ranging from difficulty with finding the right words, to severe memory disturbance or confusion - occasionally giving rise to suggestions of Alzheimer's. Some people may have a history of recurrent miscarriage, seizures, aches and pains, chronic fatigue etc. In other people the diverse neurological features have resulted in a diagnosis of multiple sclerosis - it can prove extremely difficult to distinguish between the signs and symptoms of both these conditions.

One must bear in mind that many of the symptoms that occur with APS are common and do not necessarily mean APS is the cause.

The following comprehensive list describes many of the conditions that sufferers can present with. Remember that this disorder can present differently in each individual. Some may experience only one, or several of the listed symptoms or conditions, while some will have a sudden onset of problems and some will have symptoms that manifest over a long period of time. Thus, correct testing and diagnosis become of paramount importance.