BIOLOGY 2F03 Lecture Notes - Lecture 7: Gray Platelet Syndrome, Platelet Alpha-Granule, Dense Granule
19 May 2018
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intracellular disorders are subclassified by what storage granule is problematic
intracellular disorders are more common but only give mild bleeding. platelet count and lifespan are
usually normal and ATP:ADP ratio is an important diagnostic tool.
storage pool disease - Dense granule deficiency
• Idiopathic (non-albino type)
• hermansky-pudlak syndrome
o AR disease associated with mild bleeding
o due to membrane and content abnormalities for dense granules
o oculocutaneous albinism and very bad nystagmus are features – treat with tranexamic
acid
• chediak higashi syndrome
o AR disease associated with increased risk of infections; treat with bone marrow
translpant
• wiskott-aldrich syndrome
o due to defective WASP protein expression
o associated with eczema, immune deficiency and requires splenectomy or BMT
storage pool disease = alpha granule deficiency
• Grey platelet syndrome
o AD rare disease where alpha granules are absent/empty (so platelets appear grey on
blood film)
• quebec platelet disorder
o AD disease associated with alpha granule multimerin deficiency; reduced contents
• combined storage pool disease
defects of thromboxane generation are due to COX/ thromboxane synthetase deficiencies
defects in signal transduction can be suspected if you defective aggregation responses to all agonists
4. treatment of hereditary platelet disorders requires specialist care
• Supportive measures (avoid aspirin, NSAIDs, give tranexamic acid)
• DDAVP (but not in kids as it gives hyponatraemia)
• platelet transfusion – HLA match if they will need lifelong transfusion to avoid Ab synthesis
• rF8 for Haemophil/glanzmanns patients who have developed Abs
• BMT – usually just for Bernard soullier and glanzmanns; 10% mortality at least
1.20 – PREGNANCY OESTROGENS AND THE COAGULATION SYSTEM
1. Oestrogens are associated with an increased risk of VTE
Thrombotic changes associated with oestrogens
• Increased procoagulant activity
o stimulation of Fibrinogen, F7-11, vWF, protein C resistance
• Decreased anticoagulant activity
o Inhibition of protein S and antithrombin
o the pill reduces transcriptional synthesis of protein S
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