What is antiphospholipid syndrome?

Antiphospholipid syndrome (APS) is an autoimmune disease which affects the blood and its ability to clot. An overactive immune system produces antiphospholipid antibodies (aPL), which cause the blood to clot too quickly both in veins and arteries.

The clotting can affect any vein, artery or organ in the body, and the consequences can include potentially fatal conditions such as heart attacks, strokes, and DVTs. In pregnancy, the antibodies can cause miscarriage, pre-eclampsia, small babies, early deliveries and stillbirth.

As blood flows through the entire body, antiphospholipid syndrome can present a wide variety of symptoms, not all as serious as stroke or heart attack.

People of all ages, including children, can have APS, but it tends to mainly affect the 20-50-year-old age group and women more so than men. One study has shown that 1 in 2000 people have the disorder, but it is still believed to be significantly under-recognised and under-diagnosed.

There are two main types of APS:

  • Primary antiphospholipid syndrome - the condition is not linked to any other disease and develops in isolation.
  • Secondary antiphospholipid syndrome - the condition develops along with another autoimmune disorder, usually lupus.

The good news is that APS is both potentially preventable and treatable if recognised in time; however, as the condition is relatively new in medical terms, much more research is needed until we can learn more about the causes, effects and treatments. One thing we do know is that early diagnosis of APS is crucial for patients, so APS Support UK aims to raise awareness amongst both the medical profession and the general public to achieve earlier diagnosis and the best treatment for patients.

What causes it?

We simply don’t know why people develop APS – learn more about our current understanding of the causes and triggers of the condition.

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Related conditions

Some people with APS will also have other autoimmune conditions. View our list of related conditions.

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