Protein S deficiency can cause excessive blood clotting in some people. Depending on the severity, treatment with blood thinners may be necessary.

Protein S deficiency is a rare condition that causes blood to clot too easily. Protein S is one of several proteins that helps stop your blood from making too many blood clots.

Protein S deficiency can be mild or severe. Some people inherit protein S deficiency, and others develop it as a result of another condition.

Without treatment, protein S deficiency can lead to serious and even fatal complications. Treatment is typically blood thinning medication, and the doses, duration, and exact medication can all vary, and not everyone may need them.

A protein S deficiency is rare. Mild protein S deficiency is more common than severe protein S deficiency.

Mild protein S deficiency occurs in about 1 in every 700 people. The exact rate of severe protein S deficiency is unknown.

Protein S deficiency is caused by a change or mutation to the PROS1 gene. Sometimes, this is an inherited mutation. Protein S deficiency passes down in families. Inherited mutation on the PROS1 gene from one parent results in mild protein S deficiency. Inheriting it from both parents results in severe protein S deficiency.

Protein S deficiency can also be acquired. This means it can occur when something causes a change to your PROS1 gene. This can happen as a result of:

Can COVID cause protein S deficiency?

Protein S deficiencies have long been linked with infections. COVID-19 has been linked to an increased risk of blood clots and other thrombotic conditions from the early days of the pandemic.

As more information about the COVID-19 infection has become clear, studies reported protein S deficiency in patients with COVID-19. Further research is needed.

As with most things related to COVID-19, this data is still new and still evolving. But current evidence seems to suggest that COVID-19 could have a link to protein S deficiencies.

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One of the most common symptoms of a protein S deficiency is deep vein thrombosis (DVT). DVT is an often-painful clot that forms in the legs. It can cause swelling and can increase the risk of a serious condition called a pulmonary embolism, which occurs occurs when the arteries that supply blood to your lungs become blocked by a clot.

A protein S deficiency can also cause blood clots during pregnancy, and children with severe protein S have an increased stroke risk.

Diagnosing a protein S deficiency is based primarily on looking at your symptoms, medical history, and family medical history. Blood work can help confirm the diagnosis. Typically, a doctor will suspect a protein S deficiency if you have:

  • developed repeated blood clots
  • a family history of blood clots
  • a blood clot before age 50 without a clear cause
  • a venous thrombosis in a non-standard place like your liver, intestines, or brain

Bloodwork will look for the activity level of protein S and specific enzymes in your blood. You might also have molecular genetic testing to confirm a diagnosis by looking for the mutation in the PROS1 gene, but this test isn’t always part of the standard diagnosis process.

Treatment for a protein S deficiency can vary. For instance, if you have a protein S deficiency but haven’t had a blood clot, you might not need treatment at all unless your circumstances change.

Some people who’ve never had blood clots but who have a protein S deficiency need treatment only at certain times, like if they’re going to have surgery, or they’re injured.

If you have a protein S deficiency and experienced blood clots, blood thinners are the most common medication choice. This includes options like heparin and warfarin. The exact blood thinner, and the exact dose will depend on you and on how your body reacts to the medication.

How is protein S deficiency treated in pregnancy?

People who have a protein S deficiency often require additional treatment during pregnancy. Often, this means that people who don’t typically need to receive blood thinner treatment for their mild protein S deficiency will need to take a blood thinner during pregnancy.

It can also mean that people who already take a blood thinner might need to increase their dose or change their medication. This is done to prevent miscarriage, so it’s important to discuss the best options for treatment with your doctor if are pregnant and have protein S deficiency.

Protein S deficiency is a rare condition that causes the blood to clot too quickly. It can lead to blood clots and DVT.

Some people inherit this condition. Others develop it as a result of another condition, like an infection, kidney disease, or liver disease.

Treatment for Protein S deficiency varies. People who don’t experience blood clots often only need treatment in specific instances, like before surgery or during pregnancy. People who do experience blood clots are most often treated with blood thinners.

The outlook for protein S deficiency can also vary. The condition is chronic for people with inherited protein S deficiency, but can often be resolved completely for people who acquired the condition as a result of another condition.