What Is Bernard-Soulier syndrome?

Bernard-Soulier syndrome (BSS) is a rare condition that affects how your blood clots. Normally, clotting helps stop bleeding after an injury. But in BSS, that process doesn’t work as it should.

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People with BSS have fewer platelets, and the platelets they do have are larger than normal. Platelets are tiny cells that help form clots. Because of these differences, people with BSS tend to bruise easily and bleed more than usual.

Experts think BSS affects about 1 in 1 million people worldwide. But it might be more common than we realize because it’s often missed or mistaken for something else.

Symptoms and Causes

Symptoms of Bernard-Soulier

Most people with BSS show signs early in life. You or your child may notice:

Bleeding gums
Easy bruising, even from small bumps
Frequent nosebleeds
Heavy periods (if menstruating)
Long-lasting bleeding after small cuts
Tiny red or purple spots under skin (petechiae)

These symptoms may vary from person to person. Some may have mild issues, while others bleed more severely.

Bernard-Soulier causes

Bernard-Soulier syndrome is a genetic condition. That means it’s caused by a change (variation) in your genes and is present at birth. You inherit it from one or both of your biological parents.

This condition is linked to changes in the GP1BA, GP1BB or GP9 genes. These genes help control how your body forms blood clots.

Risk factors

You’re more likely to have BSS if both your parents carry the gene mutation (autosomal recessive). In some cases, just one parent can pass it down (autosomal dominant).

Complications of this condition

The biggest risk with BSS is serious bleeding. Other problems may include:

Infections from blood transfusions
Reactions to blood transfusions
Low iron levels (iron deficiency anemia)

Thankfully, most people with BSS can avoid serious issues with the right care and precautions from their healthcare team.

Diagnosis and Tests

How doctors diagnose this condition

Healthcare providers use blood tests to check for Bernard-Soulier syndrome. These tests look at how many platelets you have and if there are changes in the genes that cause BSS. Your provider might also look at your blood under a microscope to see if your platelets are bigger than normal.

Another test, called platelet flow cytometry, checks for certain proteins on your platelets. This helps confirm the diagnosis.

Management and Treatment

Bernard-Soulier syndrome treatment

There’s no cure for Bernard-Soulier syndrome, but treatment can help manage symptoms and reduce bleeding risks. Your provider may recommend:

Platelet transfusions: Often used during surgery or after serious bleeding, these provide healthy platelets to support clotting.
Antifibrinolytic therapy: Medications like tranexamic acid (Cyklokapron®) help slow or stop bleeding, especially during dental work or minor injuries.

Your care team may also advise avoiding activities or medications that increase bleeding risk. In some cases, they’ll create a personalized emergency plan, including when to seek immediate care.

When should I see my healthcare provider?

If you have BSS, it’s important to watch for signs that you need medical attention. Call your provider if you:

Bleed when brushing your teeth, even with a soft toothbrush
Can’t stop bleeding after an injury
Have frequent or worsening nosebleeds
Have unusually heavy or prolonged menstrual periods
Notice new or large bruises without an obvious cause

Quick treatment can help prevent more serious complications. Always err on the side of caution and reach out to your care team with concerns.

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Outlook / Prognosis

What can I expect if I have this condition?

Treatment can help manage symptoms and prevent complications. Your healthcare provider may recommend that you:

Avoid medicines that increase bleeding risk, like aspirin, NSAIDs or some allergy medications
Learn how to stop nosebleeds at home.
Limit alcohol and sugary foods that affect platelet count.
Sign up with an emergency center that’s ready to treat serious bleeding.
Take iron supplements if needed.
Use a soft toothbrush to protect your gums.
Wear a medical ID bracelet.

Most people with BSS can live normal, active lives. But you’ll need to take precautions. Avoid high-risk activities like contact sports and check in regularly with your primary care provider. You may also need a platelet transfusion before any planned surgery.

Additional Common Questions

What other conditions look like BSS?

Other bleeding disorders with similar symptoms include:

If you have signs of a bleeding problem, a blood specialist can help find out what’s going on and how to treat it.

A note from Cleveland Clinic

There’s no way to prevent being born with Bernard-Soulier syndrome (BSS). But having BSS doesn’t mean you have to settle for a less active life. You may need to take extra care to avoid injuries that could lead to bleeding. But with the right treatment and support, many people with BSS live full, healthy lives. And you’re not alone. Your healthcare team is here to help, so reach out whenever you have questions or need support.

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