Anomalies of Dense Platelet Granules

Study Overview
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Brief Summary
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The study aims to know the overall prevalence of granular deficits and their breakdown by type (anomaly of number, content or secretion) in a population of patients with hemorrhagic symptomatology after exclusion of other known causes. This study consists also to evaluate the association between the presence of a deficit in dense granules and (1) the intensity of the hemorrhagic phenotype (hemorrhagic score) (2) the nature of hemorrhages (post-operative, spontaneous, atypical...) -Evaluate the association between the type of deficit in dense granules and (1) the intensity of the hemorrhagic phenotype (hemorrhagic score) (2) the nature of hemorrhages (post-operative, spontaneous, atypical...)

Detailed Description
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Patients will be recruited during the exploration visit (v0) or the confirmation/typing visit (v1) according to their follow-up. Exploration visit (v0): inclusion of patients without prior platelet exploration, and study of their dense platelet granules. Confirmation/typing visit (v1): verification of the persistence of anomalies detected in patients with an abnormality identified during v0 (no later than 6 months after v0) and in patients for whom a dense granules anomaly has already been identified during their standard management prior to the start of the study. Completion of complementary examinations to complement the typing of the granular anomaly and molecular analysis for family cases

Official Title
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Diagnosis of Platelet Dense Granules Anomalies in Unexplained Hemorrhagic Syndromes

Conditions
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Spontaneous Induced Unexplained Haemorrhagic

Intervention / Treatment
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* Other: Haemostasis consultation
* Biological: Standard management of patients suspected of thrombopathy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult or child patient ≥ 2 years Having a hemorrhagic score ISTH > 3 for men, > 5 for women and > 2 for children. With no abnormal coagulation (defined by normal TP and TCK or activity ≥ 50% of FII, FV, FVII, FX, FVIII, FIX, FXI) no deficiency of Willebrand factor (defined by a cofactor activity with Ristoctin (VWF: RCo < 50%)) no a known major thrombocytopenia/thrombopathy linked to a deficiency of one of the major platelet receptors Information of the patient and/or his legal representative present Exclusion Criteria: Inability or refusal of compliance with research requirements Thrombocytopenia < 100 G/L Treatments interfering with platelet functions within 10 days prior to inclusion Malignant hemopathy

Ages Eligible for Study
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Minimum Age: 2 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Children and adults with unexplained hemorrhagic syndrome<br>Patients with spontaneous or induced hemorrhagic manifestations who are present for a consultation to investigate a thrombopathy or during follow-up consultations as part of their usual care. | Other: Haemostasis consultation<br>* Haemostasis consultation<br>Biological: Standard management of patients suspected of thrombopathy<br>* Standard management of patients suspected of thrombopathy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Platelet response to different agonists | Us of some low-dose agonists such as ADP, epinephrine or collagen, which are particularly susceptible to granular defects, on platelet-rich plasma (PRP) prepared from the patient's blood sample to be explored | Baseline (M0) | 
| Platelet response to different agonists | Use of some low-dose agonists such as ADP, epinephrine or collagen, which are particularly susceptible to granular defects, on platelet-rich plasma (PRP) prepared from the patient's blood sample to be explored | At 6 months | 
| Granular Delta content | Dosage of platelet serotonin by measuring platelet serotonin by HPLC. | Baseline (M0) | 
| Measurement of ATP | The measurement is based on the principle of bioluminescence with a two-step transformation reaction of luciferin in the presence of luciferase, this reaction requiring the presence of ATP | Baseline (M0) | 
| Measurement of ATP | The measurement is based on the principle of bioluminescence with a two-step transformation reaction of luciferin in the presence of luciferase, this reaction requiring the presence of ATP | At 6 months | 
| Measurement of granules opacity | Delta granules contain calcium, which makes them naturally opaque to electrons and thus allows their direct visualization in electronic microscopy. | Baseline (M0) | 
| Measurement of granules opacity | Delta granules contain calcium, which makes them naturally opaque to electrons and thus allows their direct visualization in electronic microscopy. | at 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hemorrhagic risk assessment | Evaluation using the ISTH score | Baseline (M0) | 
| Typage of delta granules anomalies | Fib-SEM technic by focussed ion beam scanning which allows a 3D reconstitution of the platelets and thus to visualize any empty granules | At 6 months | 
| Genetic anomalies of delta granules | Sequencing on a broad set of genes involved in platelet function. Bioinformatic analysis is carried out using BWA-MEM software (Alignment on the genome version HG19) | At 6 months | 
| Prothrombin consumption | Evaluated by% of residual Thrombin after plasma coagulation | Baseline (M0) | 
| Prothrombin consumption | Evaluated by% of residual Thrombin after plasma coagulation | at 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dense platelet granules, Thrombopathy, Hemorrhagic symptomatology