Bernard-Soulier Syndrome: The Rare Bleeding Disorder That Leaves You With Fewer, Larger Platelets — and Why Most People Still Live Full, Active Lives
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD. Last reviewed October 13, 2026. This content is for educational purposes and is not medical advice.
Quick Answer
Bernard-Soulier syndrome is a rare, inherited blood disorder in which platelets are fewer and larger than normal, making clotting harder [1] [2]. It causes easy bruising, nosebleeds, bleeding gums, heavy periods and prolonged bleeding from small cuts, usually starting early in life [1] [2]. There is no cure, but platelet transfusions and tranexamic acid control bleeding [1] [2], and most people live full, active lives [1].
What the research says
The genes behind BSS are well mapped, and most patients carry the same change on both gene copies. In a pooled analysis of 211 families, mutations were found in GP9 (44%), GP1BA (28%), and GP1BB (28%), and 85% of the affected individuals had homozygous mutations, which fits the recessive inheritance described below (Savoia et al., Hum Mutat, 2014) [4].
Platelet transfusion is still the main treatment, with backup options when it stops working. An expert review reports that recombinant factor VIIa is advised for patients whose bodies have made antibodies against transfused platelets, and stem cell transplantation is suggested for refractory cases. It also notes that milder, single-copy forms are often diagnosed later in life and mistaken for immune thrombocytopenia (Kaya, Semin Thromb Hemost, 2025) [3].
Pregnancy needs a plan. In a literature review of 51 deliveries in women with BSS, postpartum hemorrhage occurred in 52.9% (27/51), and it was less common in women who received preventive treatment around delivery. The authors note there is no high-quality evidence on the best approach because the disease is so rare (Sarıdoğan et al., Z Geburtshilfe Neonatol, 2023) [5].
What Is Bernard-Soulier Syndrome?
Bernard-Soulier syndrome (BSS) is a rare condition that affects how your blood clots [1]. Normally, clotting helps stop bleeding after an injury. But in BSS, that process doesn't work as it should.
People with BSS have fewer platelets, and the platelets they do have are larger than normal [1] [2]. Platelets are tiny cells that help form clots. Because of these differences, people with BSS tend to bruise easily and bleed more than usual [1].
Experts think BSS affects about 1 in 1 million people worldwide [1] [2]. But it might be more common than we realize because it's often missed or mistaken for something else [1] [2].
Why Do People With Bernard-Soulier Syndrome Bleed So Easily?
The answer comes down to the platelets. Think of platelets as your body's emergency sealant — tiny cells that rush to a wound and stick together to form a clot that stops the bleeding.
In Bernard-Soulier syndrome, two things go wrong with that sealant supply: you have fewer platelets than normal, and the platelets you do have are bigger than normal. That combination means clots don't form the way they should, so cuts take longer to stop bleeding and bruises appear from even small bumps.
What Are the Symptoms of Bernard-Soulier Syndrome?
Most people with BSS show signs early in life [1] [2]. Symptoms may vary from person to person — some may have mild issues, while others bleed more severely [1].
The six main signs are bleeding gums, easy bruising even from small bumps, frequent nosebleeds, heavy periods (if menstruating), long-lasting bleeding after small cuts, and petechiae — tiny red or purple spots under the skin [1].
Symptom | What to look for |
Bleeding gums | Gums that bleed, even during gentle brushing |
Easy bruising | Bruises from small bumps that would barely bother most people |
Frequent nosebleeds | Nosebleeds that happen often and may be hard to stop |
Heavy periods | Menstrual bleeding that is heavier than usual (if menstruating) |
Long-lasting bleeding | Small cuts that keep bleeding far longer than they should |
Petechiae | Tiny red or purple spots that appear under the skin |
How severe is it?
Severity varies a lot from person to person. Some people have only mild bleeding issues, while others bleed much more severely.
What Causes Bernard-Soulier Syndrome?
Bernard-Soulier syndrome is a genetic condition [1]. 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 [1].
The condition is linked to changes in the GP1BA, GP1BB, or GP9 genes [1] [2] [4]. These genes help control how your body forms blood clots.
How is it passed down in families?
You're more likely to have BSS if both your parents carry the gene mutation — this inheritance pattern is called autosomal recessive [1] [2]. In some cases, just one parent can pass it down, which is called autosomal dominant [1] [2].
What Are the Complications of Bernard-Soulier Syndrome?
The biggest risk with BSS is serious bleeding [1]. Other problems may include infections from blood transfusions, reactions to blood transfusions, and low iron levels (iron deficiency anemia) [1].
Thankfully, most people with BSS can avoid serious issues with the right care and precautions from their healthcare team.
How Is Bernard-Soulier Syndrome Diagnosed?
Healthcare providers use blood tests to check for Bernard-Soulier syndrome. These tests look at how many platelets you have and whether there are changes in the genes that cause BSS [1].
Your provider might also look at your blood under a microscope to see if your platelets are bigger than normal [1] — a distinctive feature of this syndrome.
Another test, called platelet flow cytometry, checks for certain proteins on your platelets. This helps confirm the diagnosis [1] [2].
Test | What it checks |
Platelet count (blood test) | How many platelets you have — usually low in BSS |
Blood under a microscope | Whether your platelets are bigger than normal |
Gene testing | Changes in the GP1BA, GP1BB, or GP9 genes |
Platelet flow cytometry | Certain proteins on your platelets; helps confirm the diagnosis |
What conditions look like BSS?
Other bleeding disorders with similar symptoms include Glanzmann thrombasthenia, hemophilia, May-Hegglin anomaly, and von Willebrand disease [1]. If you have signs of a bleeding problem, a blood specialist can help find out what's going on and how to treat it.
How Is Bernard-Soulier Syndrome Treated?
There's no cure for Bernard-Soulier syndrome [1], but treatment can help manage symptoms and reduce bleeding risks.
Treatment | How it works |
Platelet transfusions | Provide healthy platelets to support clotting; often used during surgery or after serious bleeding |
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 [1].
What everyday precautions help?
Your healthcare provider may recommend avoiding medicines that increase bleeding risk, like aspirin, NSAIDs, or some allergy medications; learning how to stop nosebleeds at home; limiting alcohol and sugary foods that affect platelet count; signing up with an emergency center that's ready to treat serious bleeding; taking iron supplements if needed; using a soft toothbrush to protect your gums; and wearing a medical ID bracelet [1].
Most people with BSS can live normal, active lives [1] [2]. But you'll need to take precautions: avoid high-risk activities like contact sports, check in regularly with your primary care provider, and you may need a platelet transfusion before any planned surgery [1].
When Should You Call Your Healthcare Provider?
People with Bernard-Soulier syndrome (BSS) should watch for bleeding and bruising signs that need medical attention, since quick treatment can help prevent serious complications. 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.
Can You Prevent Bernard-Soulier Syndrome?
There's no way to prevent being born with Bernard-Soulier syndrome [1]. It's inherited — you're born with the gene change, and nothing you do before or after birth changes that.
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 there to help, so reach out whenever you have questions or need support.
What's the Bottom Line?
Bernard-Soulier syndrome is a rare, inherited blood disorder — affecting about 1 in 1 million people worldwide — that disrupts the body's clotting system by leaving you with fewer platelets that are also larger than normal. The signs usually show up early in life: bleeding gums, easy bruising from small bumps, frequent nosebleeds, heavy periods, small cuts that won't stop bleeding, and tiny red or purple spots under the skin. It's caused by changes in the GP1BA, GP1BB, or GP9 genes, passed down from one or both parents, and it's often missed or mistaken for other bleeding disorders like hemophilia or von Willebrand disease. Diagnosis relies on blood tests, a look at your platelets under a microscope, gene testing, and platelet flow cytometry. There is no cure, but platelet transfusions and antifibrinolytic medications like tranexamic acid keep bleeding under control, and a set of smart precautions — avoiding aspirin, NSAIDs, and contact sports; wearing a medical ID bracelet; using a soft toothbrush — goes a long way. Most people with BSS live normal, active lives, and with the right care and support, they can avoid the most serious complications. If bleeding signs run in your family or show up early in your child's life, see a healthcare provider — and if bleeding won't stop after an injury, seek care right away.
If you or your child bruises easily or bleeds more than usual, don't brush it off — explore Rinnit.com's library of clear, practical health guides and start the right conversation with your healthcare provider today.
Frequently Asked Questions
What is Bernard-Soulier syndrome?
A rare, inherited blood disorder where you have fewer platelets than normal and the ones you have are larger than normal, so your blood doesn't clot as it should.
What does BSS stand for?
Bernard-Soulier syndrome — a bleeding disorder named after the doctors who first described it.
Is Bernard-Soulier syndrome genetic?
Yes. It's caused by changes in the GP1BA, GP1BB, or GP9 genes and is present at birth, inherited from one or both biological parents.
How rare is Bernard-Soulier syndrome?
Experts think it affects about 1 in 1 million people worldwide — but it may be more common than we realize because it's often missed or mistaken for something else.
What are the symptoms of Bernard-Soulier syndrome?
Bleeding gums, easy bruising from small bumps, frequent nosebleeds, heavy periods, long-lasting bleeding after small cuts, and petechiae (tiny red or purple spots under the skin).
What are petechiae?
Tiny red or purple spots that appear under the skin — one of the signs of BSS.
Why are platelets important?
Platelets are tiny cells that help form clots, which stop bleeding after an injury. In BSS you have fewer of them and they're larger than normal.
How is Bernard-Soulier syndrome inherited?
Most often, both parents carry the gene mutation (autosomal recessive). In some cases, just one parent can pass it down (autosomal dominant).
How is BSS diagnosed?
With blood tests that check your platelet count, a look at your blood under a microscope to check platelet size, gene testing, and platelet flow cytometry, which checks for certain proteins on your platelets.
What conditions look like Bernard-Soulier syndrome?
Glanzmann thrombasthenia, hemophilia, May-Hegglin anomaly, and von Willebrand disease — which is why a blood specialist may be needed to confirm the diagnosis.
Is there a cure for Bernard-Soulier syndrome?
No, but treatment manages symptoms and reduces bleeding risks.
What treatments are used for BSS?
Platelet transfusions (often during surgery or after serious bleeding) and antifibrinolytic medications like tranexamic acid (Cyklokapron) to slow or stop bleeding, especially during dental work or minor injuries.
What medicines should people with BSS avoid?
Medicines that increase bleeding risk, like aspirin, NSAIDs, or some allergy medications.
Can people with BSS play sports?
Most can live normal, active lives, but they should avoid high-risk activities like contact sports and may need a platelet transfusion before any planned surgery.
Can Bernard-Soulier syndrome be prevented?
No — there's no way to prevent being born with it. But with the right treatment and support, many people with BSS live full, healthy lives.
Related Reading
Hemophilia: Symptoms, Causes, Diagnosis & Treatment Guide: another inherited bleeding disorder that can look similar to BSS.
MPV Blood Test (Mean Platelet Volume): Normal Range, High and Low Results explains the blood test that measures platelet size and helps evaluate this condition.
Learn more in our guide to Platelet Count (PLT) Blood Test: Normal Range, Low and High Results Explained.
References
Cleveland Clinic. Bernard-Soulier Syndrome. Cleveland Clinic. Updated July 14, 2025. https://my.clevelandclinic.org/health/diseases/24110-bernard-soulier-syndrome
Almomani MH, et al. Bernard-Soulier Syndrome. StatPearls. Updated January 11, 2024. https://www.ncbi.nlm.nih.gov/books/NBK557671/
Kaya Z. Bernard-Soulier Syndrome: A Review of Epidemiology, Molecular Pathology, Clinical Features, Laboratory Diagnosis, and Therapeutic Management. Semin Thromb Hemost. 2025;51(2):209-218. PMID 39191409. https://doi.org/10.1055/s-0044-1789184
Savoia A, et al. Spectrum of the mutations in Bernard-Soulier syndrome. Hum Mutat. 2014;35(9):1033-45. PMID 24934643. https://doi.org/10.1002/humu.22607
Sarıdoğan E, et al. Bernard-Soulier Syndrome from the Perspective of the Obstetrician: A Case Report with a Review of the Literature. Z Geburtshilfe Neonatol. 2023;227(3):168-178. PMID 36889343. https://doi.org/10.1055/a-2024-0819
Medical disclaimer
This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions about a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read here. If bleeding will not stop after an injury, seek emergency medical care right away.
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