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Bernard-Soulier syndrome
This syndrome affects the blood's ability to clot effectively due to defects in specific platelet proteins. Individuals with Bernard-Soulier syndrome often experience easy bruising, nosebleeds, and prolonged bleeding, which can range in severity.
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Overview
Bernard-Soulier syndrome (BSS) is a rare genetic condition that affects the way blood clots. It is characterised by unusually large platelets (thrombocytes), which are also deficient in a specific protein complex (GPIb-IX-V) essential for their function [PMID:17004245]. Because of this defect, platelets cannot properly attach to sites of injury in blood vessels, preventing the formation of a stable blood clot.
This condition can lead to a range of bleeding symptoms, from mild bruising to severe haemorrhage. It is typically diagnosed in childhood or infancy, often after prolonged bleeding from minor injuries or surgeries. The severity of bleeding can vary significantly between individuals.
Symptoms & clinical features
Individuals with Bernard-Soulier syndrome commonly experience symptoms related to impaired blood clotting. These can include frequent nosebleeds (epistaxis), easy bruising, and prolonged bleeding after minor cuts, dental procedures, or surgery [PMID:15336049]. Women may experience heavy or prolonged menstrual periods (menorrhagia).
Internal bleeding, such as gastrointestinal haemorrhage or bleeding into joints, can also occur but is less common. In some severe cases, bleeding in the brain may be a concern. The platelet count may be low, but the defining feature is the presence of abnormally large platelets that do not function correctly.
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Affected organs
Bernard-Soulier syndrome primarily affects the blood and the body's clotting system. Platelets, which are small cell fragments in the blood crucial for stopping bleeding, are directly impacted. Consequently, any organ or tissue where bleeding can occur is potentially affected. This includes the skin (easy bruising), mucous membranes (nosebleeds, gum bleeding), and potentially internal organs, although severe internal bleeding is less frequent.
Risks & severity
The severity of Bernard-Soulier syndrome can range from mild to severe. Some individuals may only experience occasional easy bruising, while others can have significant bleeding episodes requiring medical intervention. Complications can include severe anaemia due to chronic blood loss, and, in rare instances, life-threatening haemorrhage [PMID:17004245]. The bleeding tendency is present from birth and usually continues throughout life, though symptoms might change over time or with specific events like surgery or trauma.
There is no specific age of onset as the condition is inherited and present from birth, but symptoms typically become noticeable in infancy or early childhood. The risk of bleeding complications is generally lifelong, and careful management is important to minimise these risks.
Genetic causes
Bernard-Soulier syndrome is caused by pathogenic variants (mutations) in one of three genes: GP1BA, GP1BB, or GP9. These genes provide instructions for making components of the glycoprotein Ib-IX-V (GPIb-IX-V) complex [PMID:15336049]. This complex is a crucial receptor found on the surface of platelets.
The GPIb-IX-V complex plays a vital role in the initial stages of blood clotting. It enables platelets to bind to von Willebrand factor, a protein found in the blood vessel wall, particularly at sites of injury. This binding is the very first step in forming a plug to stop bleeding. When there are pathogenic variants in GP1BA, GP1BB, or GP9, the GPIb-IX-V complex may be absent or dysfunctional, meaning platelets cannot effectively adhere to injured blood vessels, leading to impaired clot formation.
- GP1BA glycoprotein Ib platelet subunit alphaThe *GP1BA* gene provides instructions for glycoprotein Ib-alpha (GPIbα), a key component of a protein complex vital for platelet function and blood clotting.
- GP1BB glycoprotein Ib platelet subunit beta
- GP9 glycoprotein IX plateletThe GP9 gene provides instructions for glycoprotein IX, a protein crucial for normal platelet function and the blood clotting process.
Inheritance pattern
Bernard-Soulier syndrome is inherited in an autosomal recessive pattern. This means that an individual must inherit two altered copies of the causative gene - one from each parent - to develop the condition. People who inherit only one altered copy are called carriers; they typically do not show symptoms of Bernard-Soulier syndrome but can pass the altered gene on to their children.
If both parents are carriers of the same altered gene, there is a 25% chance with each pregnancy that their child will inherit two altered copies and develop Bernard-Soulier syndrome. There is a 50% chance the child will be a carrier like the parents, and a 25% chance the child will inherit two unaffected copies of the gene.
When both parents are carriers, each child has a 25% chance of being affected, 50% of being a carrier, and 25% of being unaffected.
Diagnosis & testing
Diagnosing Bernard-Soulier syndrome typically involves a combination of clinical assessment, blood tests, and genetic testing. Blood tests may reveal a low platelet count (thrombocytopenia) and abnormally large platelets (macrothrombocytopenia), which can be seen under a microscope. Platelet function tests, such as platelet aggregation studies, will show impaired platelet aggregation in response to specific stimulants but not others [PMID:15336049].
Confirmation of the diagnosis is usually made through genetic testing, which identifies pathogenic variants in GP1BA, GP1BB, or GP9. In the UK, genetic testing for inherited bleeding disorders is available through the NHS Genomic Medicine Service (GMS) pathways, often following a referral from a haematologist or clinical geneticist. Relevant NHS Genomic and Rare Disease Medicine test codes (R-codes) for inherited platelet disorders would apply.
Management & lifestyle
Management of Bernard-Soulier syndrome focuses on preventing and treating bleeding episodes. This often involves avoiding medications that can worsen bleeding, such as aspirin or non-steroidal anti-inflammatory drugs (NSAIDs). Regular monitoring by a haematologist is crucial to tailor management strategies.
During bleeding episodes, treatments may include infusions of platelets from donors, or medications that help the body's own clotting mechanisms, such as desmopressin or antifibrinolytic agents (e.g., tranexamic acid). For severe or uncontrolled bleeding, procedures to stop bleeding directly may be necessary. Women with menorrhagia may benefit from specific gynaecological treatments. Individuals with Bernard-Soulier syndrome should carry medical identification and inform healthcare professionals about their condition before any medical procedures, including dental work or surgery.
Lifestyle considerations involve avoiding activities with a high risk of injury and educating oneself and family members about managing bleeding. Genetic counselling is also recommended for affected individuals and their families.
UK care pathway
In the UK, individuals suspected of having Bernard-Soulier syndrome would typically be referred by their GP to a haematologist or a paediatrician if a child is affected. Following initial investigations, if an inherited platelet disorder is suspected, a referral to a clinical genetics service is often made. The clinical genetics team, which may include genetic counsellors, can arrange genetic testing through the NHS Genomic Medicine Service. The specific tests fall under NHS R-codes related to inherited bleeding and platelet disorders as outlined in the GMS Genomic Test Directory. Genetic counsellors can provide valuable support and information regarding inheritance, testing for family members, and the implications of a diagnosis.
Frequently asked questions
What is the life expectancy for someone with Bernard-Soulier syndrome?
Life expectancy for individuals with Bernard-Soulier syndrome is generally normal, provided the condition is properly managed. The main concern is managing bleeding episodes, particularly severe ones. Regular medical care and adherence to treatment plans can help prevent serious complications.
Can Bernard-Soulier syndrome be cured?
Currently, there is no cure for Bernard-Soulier syndrome. Management focuses on preventing bleeding and treating bleeding episodes symptomatically. Research into genetic therapies is ongoing for many genetic conditions, but these are not yet available for Bernard-Soulier syndrome.
What should I do if I am a carrier of Bernard-Soulier syndrome?
If you are a carrier, you typically do not experience symptoms. You should consider genetic counselling to understand the implications for future pregnancies and family planning. This can help you understand the chances of passing the altered gene to your children.
Are there any activities I should avoid if I have Bernard-Soulier syndrome?
It is generally advised to avoid activities that carry a high risk of injury, especially those that could lead to head trauma or severe bruising. Contact sports may need to be approached with caution or avoided altogether. Your haematologist can provide personalised advice based on your individual condition and severity.
Is Bernard-Soulier syndrome a type of haemophilia?
No, Bernard-Soulier syndrome is not a type of haemophilia. Both are inherited bleeding disorders, but they affect different components of the blood clotting system. Haemophilia involves deficiencies in specific clotting factors (proteins), whereas Bernard-Soulier syndrome affects the function and structure of platelets themselves.
References
- Kaya Z. Bernard-Soulier Syndrome: A Review of Epidemiology, Molecular Pathology, Clinical Features, Laboratory Diagnosis, and Therapeutic Management. Seminars in thrombosis and hemostasis. 2025. PMID: 39191409
- Berndt MC, Andrews RK. Bernard-Soulier syndrome. Haematologica. 2011. PMID: 21357716
- Almomani MH, Mangla A. Bernard-Soulier Syndrome. 2026. PMID: 32491603
- Sandrock-Lang K, Wentzell R, Santoso S. Inherited platelet disorders. Hamostaseologie. 2016. PMID: 25707719
- Berndt MC, Fournier DJ, Castaldi PA. Bernard-Soulier syndrome. Bailliere's clinical haematology. 1989. PMID: 2550101
- Wu R, Salehi F, Redecke V. Murine hematopoietic progenitor cell lines with erythroid and megakaryocyte potential. Nature communications. 2025. PMID: 40775216
- López JA, Andrews RK, Afshar-Kharghan V. Bernard-Soulier syndrome. Blood. 1998. PMID: 9616133
- Andrews RK, Berndt MC. Bernard-Soulier syndrome: an update. Seminars in thrombosis and hemostasis. 2013. PMID: 23929303