Glanzmann's thrombasthenia: an overview

Immune gene polymorphisms associated with poor response to platelet transfusion and recombinant factor VII administration in Glanzmann thrombasthenia

INTRODUCTION

Poor response to platelet and recombinant factor VII administration is a major problem in patients with Glanzmann Thrombasthenia (GT). The risk factors associated with poor response to treatment in these patients are unknown. Some genetic variations of cytokines may contribute to therapy resistance.

AIMS

We evaluated, for the first time, whether genetic polymorphisms on cytokine genes are related to poor treatment response in GT patients.

METHODS

We enrolled 30 patients with GT (15 resistant and 15 non-resistant) and 100 healthy controls. Gene polymorphisms of IL-10 and TNF-α were analysed using TaqMan Realtime PCR, and IL-1, IL-1R1 and IL-1RN were investigated with the RFLP method. In-silico analyses were performed to predict the potential impact of these polymorphisms.

RESULTS

In the resistant group, all patients had a variant of the IL-10 gene at the -1082 position (rs1800896), with a GG genotype that was significantly more frequent than the non-resistant group. Analysis between healthy controls and GT patients revealed a probable correlation between rs3783550, rs3783553, rs3917356 and rs2234463 and GT. The In-silico study indicated that TNF-α rs1800629 and IL-10 rs1800896 polymorphisms result in different allelic expressions which may contribute to poor response to therapy.

CONCLUSIONS

These findings suggest that polymorphisms in the IL-10 and IL-1 receptor antagonist genes may play a role in poor therapy response in GT patients. In addition, some polymorphisms in IL-1α, IL1-β, IL-1R1 and IL-R antagonists might be involved in the GT progression.

Two case reports of Glanzmann thrombasthenia with intracranial hemorrhage and a review of the literature

Background

Glanzmann's thrombasthenia (GT) is a rare autosomal recessive disorder characterized by impaired platelet function. Symptoms range from mild to life-threatening bleeding. However, it is extremely rare for a patient to have intracranial bleeding. This study presents two cases of GT: one with a spontaneous epidural hematoma (EDH) and the other with a subarachnoid hemorrhage due to traumatic causes. The discussion that follows then derives relevant supporting insights through a review of the literature.

Case Description

Case Report 1: A 9-year-old girl with a known case of GT presented to an emergency department with a severe headache but no other complaints or history of trauma. The physical examination was normal. Computed tomography (CT) head without contrast revealed multiple EDHs with no midline shift. She received factor VII, tranexamic acid, and platelets transfusion and was admitted to the intensive care unit to be managed conservatively. After a month, a CT head follow-up showed complete resolution of all hematomas. Case Report 2: A 20-year-old male with a known case of GT was brought to the hospital with a history of loss of consciousness for several minutes after a road traffic accident. He suffered from a headache on regaining consciousness and received analgesia. CT head showed diffuse subarachnoid hemorrhage. He was managed with factor VII, tranexamic acid, and platelets transfusion and was admitted to an intermediate care unit for close observation.

Conclusion

In a GT patient with intracranial hemorrhage, conservative management with close clinical observation and platelet transfusion in combination with recombinant activated factor VII and/or antifibrinolytics can be safely conducted.

Description and Clinical Management of Patients With Glanzmann's Thrombasthenia in a University Hospital, a Referral Center Specialized in Hemostasis, in Bogotá, Colombia

Introduction

Glanzmann's thrombasthenia (GT) is an autosomal recessive disorder of platelets caused by a deficiency in the glycoprotein IIb-IIIa. Bleeding from the skin, mucous membranes, and ecchymosis are symptoms manifested starting in early childhood. There may also be major bleeding conditions as a result of surgical procedures or trauma. The treatment is based on platelet transfusions, antifibrinolytic agents, and recombinant activated factor VII (rFVIIa).

Objective

To describe the demographic and clinical characteristics as well as the main treatment strategies used during bleeding events or procedures for patients diagnosed with GT that required inpatient attention at a university hospital, a referral center specialized in hemostasis, in the city of Bogota.

Materials and methods

A descriptive retrospective cohort study was done over a period of 10 years that included nine patients over 18 years of age diagnosed with GT.

Results

A total of 34 admissions were reported, 23 due to bleeding and 11 for scheduled surgery. Some of the admissions for bleeding (38%) (n=13) required surgical procedures. Overall, 23 surgical procedures were done, six of which were classified as major. Seventy-seven percent of the patients were women with a median age of 37. Their most common symptoms were mucosal and genitourinary bleeding. The use of antifibrinolytics was registered in 28 events, followed by the use of platelet transfusion in 19, and the use of rFVIIa in 17. The average hospital stay was eight days.

Conclusion

The characteristics registered and the treatments established for this cohort of Colombian patients with GT are similar to those reported in other hospitals around the world. GT presents diagnostic and therapeutic challenges and, therefore, acquiring more knowledge about this pathology is needed within this context.

Flow cytometric analysis of platelet surface glycoproteins in the diagnosis of thirty-two Turkish patients with Glanzmann thrombasthenia: a multicenter experience

Background/aim

Glanzmann thrombasthenia (GT) is a rare autosomal recessively inherited bleeding disorder characterized by the quantitative (type 1 and type 2) or qualitative (type 3) deficiency in platelet membrane glycoprotein (GP) IIb/IIIa (CD41a/CD61) fibrinogen receptors. In type 1, 2, and 3, CD41a/CD61 expression is 5%, 5%–20% and above 20%, respectively. In this study, diagnosis of GT was confirmed and subgroups were identified in 32 Turkish patients by flow cytometry analysis.

Materials and methods

CD41a/CD61 expression levels in platelet-rich plasma (PRP) obtained from peripheral venous EDTA blood samples were analyzed with a BD FACSCanto II flow cytometer (Becton Dickinson, Franklin Lakes, NJ, USA). GT subgroup analysis was performed by counting 50,000 events in the BD FACSDiva Software v6.1.3 program of the instrument.

Results

In the present study, in blood samples of 32 patients from 23 families with GT and 22 healthy controls, co-expression levels of CD41a and CD61 in PRP was analyzed. 12 out of 23 families were consistent with type 1 GT (52.2%), 4 were consistent with type 2 GT (17.4%), and 7 were consistent with type 3 GT (30.4%).

Conclusion

Especially due to consanguineous marriages, GT with various glycoprotein levels may be detected. As a result of the flow cytometry analysis of the present study with the highest GT patient population in Turkey, type 1 GT patients were the most common subgroup. In the determination of the GT subgroups; especially in the detection of type 3 GT, flow cytometry is the most sensitive glycoprotein analysis method. In addition to light transmission aggregometry, CD41a/CD61 study by flow cytometer confirms diagnosis when mutation analysis cannot be performed.

Two homozygous missense mutations in ITGB3 gene as a cause of Glanzmann Thrombasthenia in four consanguineous Pakistani pedigrees

INTRODUCTION

Glanzmann thrombasthenia (GT) is most common of inherited platelet disorders, resulting from quantitative/qualitative defects in platelet surface integrin αIIbβ3, encoded by ITGA2B and ITGB3 genes. Little is known about clinical and molecular characteristics of GT patients from highly consanguineous Pakistani population.

METHODS

This study analyzed the clinical and molecular spectrum of six GT patients from four unrelated but consanguineous families. Platelet surface expression of αIIbβ3 integrin was determined using flow cytometry analysis. ITGA2B and ITGB3 genes were screened for causative mutations by DNA sequencing. Detected mutations were characterized for their pathogenicity using a variety of in silico tools.

RESULTS

Glanzmann thrombasthenia patients in this study generally presented early in life, had a severe course of clinical disease with transfusion dependency for management of bleeding episodes. Molecular analysis revealed 2 homozygous missense mutations in ITGB3 gene, c.422 A˃G (p.Y141C) in three GT patients from a single pedigree with familial segregation and c.1641 C>G (p.C547W) in three unrelated GT patients from three families manifesting type I GT with severe reduction in platelet αIIbβ3 levels. In silico pathogenicity predictions, multiple sequence alignment and 3D protein modeling unanimously suggested deleterious nature of the detected mutations, possibly due to aberrant disulfide bonding. Of note, clinical diversity was observed even among GT patients with same mutation in GT1 family.

CONCLUSION

This study provides an initial yet important account of clinical and genetic characterization of GT in local patients which may spark further studies to help molecular diagnosis, optimal disease management, and genetic counseling based prevention efforts.

Evaluation of platelet surface glycoproteins in patients with Glanzmann thrombasthenia: Association with bleeding symptoms

Background & objectives:

Glanzmann thrombasthenia (GT) is a rare, inherited autosomal recessive disorder characterized by qualitative or quantitative deficiency of integrin αIIbβ3 [glycoprotein IIb (GPIIb)/IIIa, CD41/CD61] diagnosed by absent or reduced platelet aggregation to physiological agonists, namely, collagen, adenosine-di-phosphate, epinephrine and arachidonic acid. The objective of this study was to quantitate platelet surface GPs, classify GT patients and relate the results with the severity of bleeding and platelet aggregation studies.

Methods:

Fifty one patients of GT diagnosed by platelet aggregation studies were evaluated for the expression of CD41, CD61, CD42a and CD42b on platelet surface by flow cytometry. The association between the clinical phenotype based on bleeding score and GT subtype on flow cytometric evaluation was assessed.

Results:

Twenty four (47%) patients of GT were classified as type I (as CD41/CD61 were virtually absent, <5%), six (11.8%) patients as type II (5-20% CD41/CD61) and 21 (41.2%) as type III or GT variants as they had near normal levels of CD41 and CD61. Type III GT patients had significantly lower numbers of severe bleeders (P=0.034), but the severity of bleeding did not vary significantly in type I and II GT patients. In all GT patients, mean CD41 expression was found to be lower than mean CD61 expression (P=0.002).

Interpretation & conclusions:

Type I GT was found most common in our patients and with lowered mean CD41 expression in comparison with CD61. Type III GT patients had significantly lower numbers of severe bleeders, but the severity of bleeding did not vary significantly in type I and II GT patients.

Genetics of inherited platelet disorders

The current review describes inherited platelet disorders, illustrates their clinical phenotype and molecular genetic defects. Platelets are the key molecules mediating haemostasis via adhesion, activation and clot formation at the site of injury. The inherited platelet disorders can be classified according to their platelet defects: receptor/cytoskeleton defects, secretion disorder, and signal transduction defect.

Patients with inherited thrombocytopathia present with mucous membrane bleedings (epistaxis, gingival bleeding) and may present with serious life threatening bleedings following surgery or trauma. Therefore, biochemical and molecular genetic characterization of inherited platelet disorders is important to understand these disorders and to support an efficient therapy.

Indication for allogeneic stem cell transplantation in Glanzmann’s thrombasthenia

Glanzmann’s thrombasthenia (GT) is an autosomal recessive disorder characterized by a lack of thrombocyte aggregation due to the absence of thrombocyte glycoproteins IIb and αIIbβ3. The role of haematopoietic stem cell transplantation (HSCT) in GT remains controversial. However, HSCT offers the only curative approach for patients with a severe clinical phenotype.

In this review, we will discuss the limitation of current status evidence and the specific risk of GT, in particular the alloimmunization and refractoriness to thrombocyte infusions. 19 successful HSCT in 18 GT type I patients have been reported. Mean age at transplantation was 5 years. All patients are still alive. The majority received sibling bone marrow transplant with busulfan and cyclophosphamid conditioning. GvHD incidence was within the normal range, but 10 patients showed alloimmunization of thrombocytes. Median follow up is 25 months.

Platelet function testing: from routine to specialist testing

Platelets have many functions within the haemostatic system, and when these actions are diminished for whatever reason, a bleeding tendency can manifest. Unravelling the reason(s) for this bleeding can be complex due to the multiple roles platelets perform. This review seeks to explain each level of platelet testing moving from those performed at local hospital laboratories to those performed by specialist centres and university research departments. It will examine the testing available and discuss when to move on to additional testing.

Glanzmann thrombasthenia in Pakistan: molecular analysis and identification of novel mutations

Glanzmann thrombasthenia (GT) is an inherited genetic disorder affecting platelets, which is characterized by spontaneous mucocutaneous bleeding and abnormally prolonged bleeding in response to injury or trauma. The underlying defect is failure of platelet aggregation due to qualitative and/or quantitative deficiency of platelet integrin αIIbβ3 resulting from molecular genetic defects in either ITGA2B or ITGB3. Here, we examine a Pakistani cohort of 15 patients with clinical symptoms of GT who underwent laboratory and molecular genetic analysis. In patients with a broad range of disease severity and age of presentation, we identified pathogenic mutations in ITGA2B in 11 patients from 8 different families, including 2 novel homozygous mutations and 1 novel heterozygous mutation. Mutations in ITGB3 were identified in 4 patients from 3 families, two of which were novel homozygous truncating mutations. A molecular genetic diagnosis was established in 11 families with GT, including 5 novel mutations extending the spectrum of mutations in this disease within a region of the world where little is known about the incidence of GT. Mutational analysis is a key component of a complete diagnosis of GT and allows appropriate management and screening of other family members to be performed.

NovoSeven (recombinant factor VIIa) for the treatment of bleeding episodes and perioperative management in patients with Glanzmann's thrombasthenia

Glanzmann's thrombasthenia is a rare inherited autosomal recessive bleeding disorder caused by qualitative or quantitative defects of the platelet membrane glycoprotein IIb/IIIa. The ensuing lack of platelet aggregation is frequently associated with mucocutaneous bleeding that may be variable in both frequency and intensity, ranging from minimal bruising to severe and life-threatening hemorrhages. A number of treatment modalities have been proposed to manage the bleeding episodes, which include local measures, antifibrinolytic agents, platelet transfusions and recombinant activated factor VII. The role of this bypassing hemostatic agent for treatment or prevention of bleeding episodes in Glanzmann's thrombasthenia patients is critically analyzed in this review.

Coincidence of Glanzmann's thrombasthenia with hereditary haemorrhagic telengiectasia in a man with gastrointestinal bleeding

Here we report a case of a 57-year-old man referred to our hospital with weakness, lethargy, melena, and rectorrhalgia. His physical examination and past medical history showed gingival bleeding, several episodes of epistaxis and post-surgery bleeding. Primary laboratory evaluation revealed only anaemia. Gastrointestinal findings including upper endoscopy and colonoscopy documented normal status, but balloon endoscopy illustrated telengiectasia-like lesions in the mid-jejunum. The case was suspected to be haemophilia due to the past medical history, although complete haemostatic evaluation demonstrated Glanzmann's thrombasthenia. The diagnosis of co-occurrence of hereditary haemorrhagic telengiectasia and Glanzmann's thrombasthenia was confirmed. This case revealed the coincidence of two bleeding tendencies, which, although rare, is a possible phenomenon. We recommend carrying out both primary and secondary haemostatic profiles for every patient with bleeding diathesis.

Plasma and whole blood clot strength measured by thrombelastography in patients treated with clopidogrel during acute coronary syndromes

INTRODUCTION

Treatment with clopidogrel, a selective platelet P2Y12 receptor antagonist, reduces risk of recurrent ischemic events in patients with acute coronary syndrome (ACS), by limiting platelet aggregation and activation. Stable whole blood clot formation requires activation of platelets, generation of fibrin and final fibrin crosslinks. In this study we intended to compare plasma and whole blood thrombelastography (TEG) measurements in patients during ACS.

MATERIALS AND METHODS

Whole blood and plasma samples from 32 patients with non-ST segment elevation myocardial infarction (NSTEMI) were collected after administration of clopidogrel. Whole blood and plasma fibrin clot strength (MA) were determined by TEG. Platelet aggregation was determined by light transmittance aggregometry (LTA) using adenosine 5'-diphosphate (ADP), thrombin receptor activation peptide (TRAP), or collagen as agonists. Fibrinogen and C-reactive protein (CRP) concentrations were measured by ELISA.

RESULTS

Heightened plasma fibrin clot strength was associated with increased platelet reactivity stimulated by ADP (ρ=0.536; p=0.002), TRAP (ρ=0.481; p=0.007), and collagen (ρ=0.538; p=0.01). In contrast to plasma fibrin MA, whole blood MA did not correlate with platelet aggregation. Platelet count was the primary contributor to the difference in thrombin induced whole blood MA and plasma fibrin MA. Increasing levels of CRP were associated with increased plasma fibrin clot strength and platelet reactivity.

CONCLUSIONS

Our data suggest that inflammation is associated with increased plasma fibrin clot strength and lower platelet inhibition by clopidogrel during ACS. Platelet count is a main contributor to additional contractile force of whole blood TEG as compared to plasma TEG during treatment with clopidogrel.

Classification of Iranian patients with Glanzmann's Thrombasthenia using a flow cytometric method

Glanzmann's Thrombasthenia (GT) is a rare inherited autosomal recessive platelet disorder caused by a deficiency or dysfunction of the GPIIb-IIIa receptor on platelets, which is characterized by a lack of platelet aggregation in response to multiple physiologic agonists and a life-long bleeding disorder. Flow cytometry is a rapid and highly sensitive method that can detect reduced levels of receptors, as well as absolute deficiency. The aim of this study was to classify Iranian GT patients by a flow cytometric method, and to correlate these findings with the severity of clinical bleeding. The expression of GPIIb-IIIa on the platelet surface was assessed in 123 GT patients using quantitative flow cytometry to determine the most common subtype among these patients. We used a panel of antibodies to detect the expression of glycoproteins GPIb, GPIIb, GPIIIa, as well as Integrin αv. Patients were also interviewed with regard to the severity and frequency of bleeding, according to history and gender, in order to evaluate the nature of their bleeding phenotype, and classify them as mild, moderate or severe bleeders, in accordance with the Glanzmann's Thrombasthenia Italian Team (GLATIT) protocol. In the detailed analysis of the results of our investigation, 95 out of 123 (77.5%) were classified as type I; 20 (16%) as type II with residual GPIIb-IIIa, and eight (6.5%) as GT variants. The variant type was diagnosed by the inability of GPIIb-IIIa to bind fibrinogen, as evidenced by the absence of platelet aggregation in response to physiologic agonists. There was no significant correlation between bleeding severity and different subtypes of GT. This study demonstrates that GT type I is the most common subtype among Iranian patients. There was no correlation between severity of symptoms and cytometric phenotype of the disease. The identification of families at risk may significantly decrease the incidence of the severe form of the disorder if genetic counseling is provided.

Genetic analyses of integrin signaling

The development of multicellular organisms, as well as maintenance of organ architecture and function, requires robust regulation of cell fates. This is in part achieved by conserved signaling pathways through which cells process extracellular information and translate this information into changes in proliferation, differentiation, migration, and cell shape. Gene deletion studies in higher eukaryotes have assigned critical roles for components of the extracellular matrix (ECM) and their cellular receptors in a vast number of developmental processes, indicating that a large proportion of this signaling is regulated by cell-ECM interactions. In addition, genetic alterations in components of this signaling axis play causative roles in several human diseases. This review will discuss what genetic analyses in mice and lower organisms have taught us about adhesion signaling in development and disease.

Treatment and outcomes for epistaxis in children with Glanzmann's thrombasthenia

OBJECTIVES/HYPOTHESIS

:To understand Glanzmann's thrombasthenia and provide insight to the management of epistaxis in children with this disease.

STUDY DESIGN

Retrospective chart review.

METHODS

All children diagnosed with Glanzmann's thrombasthenia and treated for epistaxis at Children's Hospitals and Clinics of Minnesota were identified and a retrospective chart review was performed. Outpatient charts, hospitalization records, and operative reports were reviewed from 1999 up to 2009 and appropriate data were extracted. The episodes of epistaxis, therapy used, complications, and success rates for controlling hemorrhage were noted.

RESULTS

Five children with a total of 63 clinical encounters for epistaxis were identified. Forty-seven encounters required hospitalization, close to half of which necessitated medical care in the intensive care unit. Nearly all encounters required infusion of hemostatic therapy with either single or multiple agents. Seventy-one procedures for life-threatening hemorrhage were performed. The most common (n = 24) intervention was administration of bovine collagen matrix, which was successful only half of the time (50%). Anterior and posterior nasal packing with or without hemostatic material completely resolved hemorrhage in 35% of the procedures.

CONCLUSIONS

To date, no form of medical or surgical intervention in children with this condition has consistently demonstrated its ability resolve nasal hemorrhage. The role of the otolaryngologist is to control bleeding during major episodes of nasal hemorrhage that do not respond to medical management. These patients usually have remarkable improvement in the frequency and severity of epistaxis in adolescence and then require much less aggressive therapy.

[Proliferative sickle cell retinopathy revealing Glanzmann thrombasthenia]

Glanzmann thrombasthenia is a rare qualitative platelet abnormality of autosomal recessive transmission caused by absence of GP IIb/IIIa and resulting in disturbance of platelet aggregation and bleeding time extension. We report the case of a 16-year-old female suffering from SC sickle cell disease and presenting with bilateral vitreous hemorrhage revealing Glanzmann thrombasthenia. Despite vitrectomy, the functional prognosis was poor. Indeed, association of a severe hemorrhagic disease and sickle cell retinopathy makes surgical management difficult.

Molecular defects in ITGA2B and ITGB3 genes in patients with Glanzmann thrombasthenia

BACKGROUND

Glanzmann thrombasthenia (GT) is an autosomal recessive inherited platelet function defect that is characterized by reduction in, or absence of, platelet aggregation in response to multiple physiologic agonists. The defect is caused by mutations in the genes encoding ITGA2B or ITGB3. This results in qualitative or quantitative abnormalities of the platelet receptor, alpha IIb-beta 3.

OBJECTIVES

The aim of this study was to identify the mutations in GT patients and to correlate these with patient phenotype.

SUBJECTS AND METHODS

A total of 45 unrelated patients with GT were enrolled in the present study to identify the causative molecular defects, and also to correlate their phenotype with their genotype. Platelet aggregation, flow cytometry, Western blotting, and mutation screening by conformation sensitive gel electrophoresis (CSGE) followed by sequencing were performed in all patients. Novel mutations were analyzed for penetrance in individual families.

RESULTS

A total of 22 novel mutations were identified in 45 unrelated GT patients. Mutations were identified in 36 of the 45 (80%) patients. Missense mutations were seen in most of the GT patients (59%). The remaining mutations were heterogeneous and were distributed throughout the length of the gene. Analysis of family members showed heterozygous mutations in all families.

CONCLUSIONS

The severe type I GT was the most common subtype found in this study. Missense mutations were identified as the defects responsible for most GT patients. Carrier detection and genetic counseling in these families is a potentially effective alternative for decreasing the burden of severe type of GT.

Endometriosis in two sisters with Glanzmann's thrombasthenia

OBJECTIVE

To present two cases of endometriosis in patients with Glanzmann's thrombasthenia (GT) and discuss the underlying pathophysiology of endometriosis.

DESIGN

Case report.

SETTING

Gynecology practice in a university teaching hospital.

PATIENT(S)

Two sisters, aged 24 and 28 years, previously diagnosed as having GT.

INTERVENTION(S)

Surgical exploration.

MAIN OUTCOME MEASURE(S)

Pathologic examination of surgical specimens was performed.

RESULT(S)

A diagnosis of endometriosis was confirmed pathologically for two sisters previously diagnosed as having GT.

CONCLUSION(S)

Women with GT seem to represent an important human model of endometriosis from which important data on the pathophysiology of endometriosis can be acquired.