PB1392 - Late Diagnosis of Two Adult Siblings with Bernard Soulier Syndrome (BSS)

Background: Bernard Soulier Syndrome (BSS) is a rare bleeding disorder with a 1 per 1 million prevalence. Most cases are diagnosed during childhood. However, like our patients, many cases are under-recognized or misdiagnosed.

Aims: To raise awareness for a rare bleeding disorder that may be misdiagnosed earlier in life.

Methods: We report two siblings with a delayed diagnosis of BSS. In both, we performed the following tests: complete blood count and blood smear, coagulation profile, von Willebrand antigen, von Willebrand activity, factor VIII activity, platelet aggregation test and electron microscopy examination of platelets.

Results: Two siblings were diagnosed with congenital thrombocytopenia of unknown cause with a platelet count of 40×109/L to 50×109/L. Their parents had normal platelet counts without any bleeding history. The first patient is a 21-year-old female who had heavy menstrual bleeding since menarche, requiring multiple hospitalizations.
The second patient is an 18-year-old male with a life-long history of easy bruising and recurrent epistaxis requiring multiple visits to the emergency department for severe nasal bleeding. In both cases, platelet aggregation tests showed a lack of agglutination with Ristocetin. Response to the other agonists was normal. Laboratory finding is shown in table 1.
We decided to manage them as follows: estrogen-containing oral contraceptive pill for menorrhagia. Tranexamic acid for mucosal bleeding. Recombinant factor VIIa (90mcg/kg) in case of severe bleeding or major surgery and consideration for platelet transfusion if the above measures did not control bleeding.

Conclusion(s): It is essential to consider BSS within the differential diagnosis of adult patients presenting with thrombocytopenia and giant platelets in the blood smear. BSS is a rare disorder that may easily have been underdiagnosed or misdiagnosed earlier in life. The presence of chronic macrothrombocytopenia in two siblings raised suspicion for an underlying genetic condition.