Bernard-Soulier syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Bernard-Soulier syndrome is a bleeding disorder associated with abnormal platelets, which are blood cells involved in blood clotting. In affected individuals, platelets are unusually large and fewer in number than usual (a combination known as macrothrombocytopenia). People with Bernard-Soulier syndrome tend to bruise easily and have an increased risk of nosebleeds (epistaxis). They may also experience abnormally heavy or prolonged bleeding following minor injury or surgery or even without trauma (spontaneous bleeding). Rarely, bleeding under the skin causes tiny red or purple spots on the skin called petechiae. Women with Bernard-Soulier syndrome often have heavy or prolonged menstrual bleeding (menorrhagia).

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Bernard-Soulier syndrome is caused by mutations in one of three genes: GP1BA, GP1BB, or GP9. The proteins produced from these genes are pieces (subunits) of a protein complex called glycoprotein (GP)Ib-IX-V. This complex is found on the surface of platelets and plays an important role in blood clotting.

The GPIb-IX-V complex can attach (bind) to a protein called von Willebrand factor, fitting together like a lock and its key. Von Willebrand factor is found on the inside surface of blood vessels, particularly when there is an injury. Binding of the GPIb-IX-V complex to von Willebrand factor allows platelets to stick to the blood vessel wall at the site of the injury. These platelets form clots, plugging holes in the blood vessels to help stop bleeding.

Most mutations in GP1BA, GP1BB, or GP9 prevent the formation of the GPIb-IX-V complex on the surface of platelets. Other mutations impair the complex's interaction with von Willebrand factor. All of these mutations impair clot formation, which leads to the excessive bleeding characteristic of Bernard-Soulier syndrome.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Most cases of Bernard-Soulier syndrome are inherited in an autosomal recessive pattern, which means both copies of the GP1BA, GP1BB, or GP9 gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene. Although most people with only one copy of the mutated gene do not show signs and symptoms of the condition, some have platelets that are slightly larger than normal or very mild bleeding abnormalities.

Rare cases of Bernard-Soulier syndrome caused by mutations in the GP1BA or GP1BB gene are inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. These individuals inherit the condition from an affected parent.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Bernard-Soulier syndrome is estimated to occur in 1 in 1 million individuals; however, some doctors think the condition is underdiagnosed and may be more common.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal bleeding · Very frequent (99-80%)

An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects.

Decreased platelet glycoprotein Ib-IX-V · Very frequent (99-80%)

Decreased cell membrane concentration of the glycoprotein complex Ib-IX-V.

Giant platelets · Very frequent (99-80%)

Giant platelets are larger than 7 micrometers and usually 10 to 20 micrometers. The term giant platelet is used when the platelet is larger than the size of the average red cell in the field. (Description adapted from College of American Pathologists, Hematology Manual, 1998).

Impaired ristocetin-induced platelet aggregation · Obligate (100%)

Abnormal response to ristocetin as manifested by reduced or lacking aggregation of platelets upon addition of ristocetin.

Macrothrombocytopenia · Very frequent (99-80%)

Gastrointestinal hemorrhage · Frequent (79-30%)

Hemorrhage affecting the gastrointestinal tract.

Menorrhagia · Frequent (79-30%)

Prolonged and excessive menses at regular intervals in excess of 80 mL or lasting longer than 7 days.

Petechiae · Frequent (79-30%)

Petechiae are pinpoint-sized reddish/purple spots, resembling a rash, that appear just under the skin or a mucous membrane when capillaries have ruptured and some superficial bleeding into the skin has happened. This term refers to an abnormally increased susceptibility to developing petechiae.

Prolonged bleeding after dental extraction · Frequent (79-30%)

Prolonged bleeding post dental extraction sufficient to require medical intervention.

Spontaneous hematomas · Frequent (79-30%)

Spontaneous development of hematomas (hematoma) or bruises without significant trauma.

Spontaneous, recurrent epistaxis · Frequent (79-30%)

Abnormal megakaryocyte morphology · Occasional (29-5%)

Any structural anomaly of megakaryocytes. Mature blood platelets are released from the cytoplasm of megakaryocytes, which are bone-marrow resident cells.

Bruising susceptibility · Occasional (29-5%)

An ecchymosis (bruise) refers to the skin discoloration caused by the escape of blood into the tissues from ruptured blood vessels. This term refers to an abnormally increased susceptibility to bruising. The corresponding phenotypic abnormality is generally elicited on medical history as a report of frequent ecchymoses or bruising without adequate trauma.

Gingival bleeding · Occasional (29-5%)

Hemorrhage affecting the gingiva.

Other findings in the same source

From: Orphanet

Additional reported features include Hematemesis (Occasional (29-5%)); Macroscopic hematuria (Occasional (29-5%)); Prolonged bleeding after surgery (Occasional (29-5%)); Asthma (Very rare (<4-1%)); Migraine (Very rare (<4-1%)); Partially duplicated kidney (Very rare (<4-1%)); Seizure (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Bernard-Soulier syndrome is Haematology, with a haematologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which blood-cell, marrow, bleeding or clotting finding matters most?
• Does the diagnosis need confirmation or a more precise subtype?
• Which symptoms or laboratory changes should trigger earlier review?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Bernard-Soulier syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.