19 Questions
What gene mutation is responsible for X-Linked Thrombocytopenia?
WAS (Wiskott-Aldrich syndrome) gene
Name two examples of genes associated with Other Inherited Thrombocytopenia.
RUNX1, ITGB3
What is the hallmark of myeloproliferative disorders associated with Primary Thrombocytosis?
A marked and persistent elevation in the platelet count
What is the clinical feature of Glanzmann Thrombasthenia?
Hemorrhagic symptoms
What platelet aggregation response is normal in Glanzmann Thrombasthenia?
Ristocetin
What is the deficiency in Glanzmann Thrombasthenia?
GPIIb/IIIa
How is Hereditary Afibrinogenemia treated?
cryoprecipitate
What is the platelet count threshold for thrombocytopenia?
Fewer than 100,000/µL
What is the most common cause of clinically important bleeding associated with thrombocytopenia?
Decrease in circulating platelets
What are the primary pathophysiologic processes involved in thrombocytopenia?
Decreased platelet production, accelerated platelet destruction, abnormal platelet distribution (sequestration)
What can result in a thrombocytopenia artifact that needs to be differentiated from true thrombocytopenia?
Poorly prepared blood smears or automated cell counts with platelet clumping or platelet satellitosis
What is the main deficiency in Bernard Soulier Syndrome?
Deficiency in GP Ib/IX/V complex (receptor of VWF)
What is the characteristic platelet aggregation response in Bernard Soulier Syndrome?
Normal aggregation response to Epinephrine, ADP, Collagen, Arachidonic acid; No aggregation response to Ristocetin
How does Bernard Soulier Syndrome differ from Von Willebrand Disease in terms of platelet function?
In Bernard Soulier Syndrome, the receptor is lacking (GP Ib/IX/V complex) rather than the substrate (VWF).
What are some of the causes of acquired platelet adhesion disorders?
Myeloproliferative, lymphoproliferative disorders, dysproteinemias; Antiplatelet antibodies; Cardiopulmonary bypass surgery; Chronic liver disease
What is the main role of the WASp gene in Wiskott-Aldrich Syndrome?
Actin cytoskeleton remodeling
Describe the Triad of symptoms seen in Wiskott-Aldrich Syndrome.
Thrombocytopenia, recurrent infections, eczema
What is the main feature of Thrombasthenia-absent Radius (TAR) syndrome?
Thrombocytopenia with absent radii
What is the deficiency observed in Quebec platelet disorder?
Multimerin
Study Notes
Thrombocytopenia
- X-Linked Thrombocytopenia is caused by a mutation in the GATA1 gene.
Inherited Thrombocytopenia
- Two examples of genes associated with Other Inherited Thrombocytopenia are: FLI1 and MPL.
Primary Thrombocytosis
- The hallmark of myeloproliferative disorders associated with Primary Thrombocytosis is an increased megakaryocyte proliferation.
Glanzmann Thrombasthenia
- Clinical feature: severe bleeding tendency.
- Platelet aggregation response to collagen and epinephrine is normal.
- Deficiency: lack of integrin αIIbβ3.
Hereditary Afibrinogenemia
- Treatment: replacement therapy with fibrinogen concentrates.
Thrombocytopenia
- Platelet count threshold: <150 x 10^9/L.
- Most common cause of clinically important bleeding: platelet dysfunction.
- Primary pathophysiologic processes: decreased platelet production or increased platelet destruction.
Artifacts in Thrombocytopenia
- In vitro platelet clumping can result in a thrombocytopenia artifact that needs to be differentiated from true thrombocytopenia.
Bernard Soulier Syndrome
- Main deficiency: lack of glycoprotein Ib-IX-V complex.
- Characteristic platelet aggregation response: absent aggregation in response to ristocetin.
- Differing from Von Willebrand Disease in terms of platelet function: Bernard Soulier Syndrome has a more severe bleeding phenotype.
Acquired Platelet Adhesion Disorders
- Causes: uremia, cardiopulmonary bypass, and extracorporeal membrane oxygenation.
Wiskott-Aldrich Syndrome
- Main role of the WASp gene: regulating actin polymerization.
- Triad of symptoms: eczema, thrombocytopenia, and recurrent infections.
Thrombasthenia-Absent Radius (TAR) Syndrome
- Main feature: bilateral radial aplasia and thrombocytopenia.
Quebec Platelet Disorder
- Deficiency: decreased platelet aggregation due to a proteolytic degradation of α-granule proteins.
Learn about qualitative platelet disorders, focusing on thrombocytopathy where platelets are qualitatively abnormal but there is a normal platelet count. Understand the clinical and laboratory features of this disorder.
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