Diagnosis of inherited platelet disorders on a blood smear: a tool to facilitate worldwide diagnosis of platelet disorders

Essentials There are many hereditary platelet disorders (HPD) but diagnosing these is challenging. We provide a method to diagnose several HPDs using standard blood smears requiring < 100 µL blood. By this approach, the underlying cause of HPD was characterized in ~25-30% of referred individuals. The method facilitates diagnosis of HPD for patients of all ages around the world.

SUMMARY

Background Many hereditary thrombocytopenias and/or platelet function disorders have been identified, but diagnosis of these conditions remains challenging. Diagnostic laboratory techniques are available only in a few specialized centers and, using fresh blood, often require the patient to travel long distances. For the same reasons, patients living in developing countries usually have limited access to diagnosis. Further, the required amount of blood is often prohibitive for pediatric patients. Objectives By a collaborative international approach of four centers, we aimed to overcome these limitations by developing a method using blood smears prepared from less than 100 μL blood, for a systematic diagnostic approach to characterize the platelet phenotype. Methods We applied immunofluorescence labelling (performed centrally) to standard air-dried peripheral blood smears (prepared locally, shipped by regular mail), using antibodies specific for proteins known to be affected in specific hereditary platelet disorders. Results By immunofluorescence labelling of blood smears we characterized the underlying cause in 877/3217 (27%) patients with suspected hereditary platelet disorders (HPD). Currently about 50 genetic causes for HPD are identified. Among those, the blood smear method was especially helpful to identify MYH9 disorders/MYH9-related disease, biallelic Bernard-Soulier syndrome, Glanzmann thrombasthenia and gray platelet syndrome. Diagnosis could be established for GATA1 macrothrombocytopenia, GFI1B macrothrombocytopenia, ß1-tubulin macrothrombocytopenia, filamin A-related thrombocytopenia and Wiskott-Aldrich syndrome. Conclusion Combining basic and widely available preanalytical methods with the immunomorphological techniques presented here, allows detailed characterization of the platelet phenotype. This supports genetic testing and facilitates diagnosis of hereditary platelet disorders for patients of all ages around the world.

Should studies on Glanzmann thrombasthenia not be telling us more about cardiovascular disease and other major illnesses?

Glanzmann thrombasthenia (GT) is a rare inherited bleeding disorder caused by loss of αIIbβ3 integrin function in platelets. Most genetic variants of β3 also affect the widely expressed αvβ3 integrin. With brief mention of mouse models, I now look at the consequences of disease-causing ITGA2B and ITGB3 mutations on the non-hemostatic functions of platelets and other cells. Reports of arterial thrombosis in GT patients are rare, but other aspects of cardiovascular disease do occur including deep vein thrombosis and congenital heart defects. Thrombophilic and other risk factors for thrombosis and lessons from heterozygotes and variant forms of GT are discussed. Assessed for GT patients are reports of leukemia and cancer, loss of fertility, bone pathology, inflammation and wound repair, infections, kidney disease, autism and respiratory disease. This survey shows an urgent need for a concerted international effort to better determine how loss of αIIbβ3 and αvβ3 influences health and disease.

Endometriosis and Glanzmann’s thrombasthenia

Glanzmann’s thrombasthenia (GT) is a rare bleeding syndrome characterized by deficiency or defect of platelet aggregation complex. The pathogenesis of endometriosis is controversial but the strongest evidence leans towards retrograde menstruation. GT probably predisposes to endometriosis. The management of women affected by this disease can be difficult due to the risk of bleeding complications, especially during surgical treatment. We describe the cases of three sisters affected by endometriosis and GT, referred to our Department, who received different therapeutic management.

αIIbβ3 variants defined by next-generation sequencing: predicting variants likely to cause Glanzmann thrombasthenia

Next-generation sequencing is transforming our understanding of human genetic variation but assessing the functional impact of novel variants presents challenges. We analyzed missense variants in the integrin αIIbβ3 receptor subunit genes ITGA2B and ITGB3 identified by whole-exome or -genome sequencing in the ThromboGenomics project, comprising ∼32,000 alleles from 16,108 individuals. We analyzed the results in comparison with 111 missense variants in these genes previously reported as being associated with Glanzmann thrombasthenia (GT), 20 associated with alloimmune thrombocytopenia, and 5 associated with aniso/macrothrombocytopenia. We identified 114 novel missense variants in ITGA2B (affecting ∼11% of the amino acids) and 68 novel missense variants in ITGB3 (affecting ∼9% of the amino acids). Of the variants, 96% had minor allele frequencies (MAF) < 0.1%, indicating their rarity. Based on sequence conservation, MAF, and location on a complete model of αIIbβ3, we selected three novel variants that affect amino acids previously associated with GT for expression in HEK293 cells. αIIb P176H and β3 C547G severely reduced αIIbβ3 expression, whereas αIIb P943A partially reduced αIIbβ3 expression and had no effect on fibrinogen binding. We used receiver operating characteristic curves of combined annotation-dependent depletion, Polyphen 2-HDIV, and sorting intolerant from tolerant to estimate the percentage of novel variants likely to be deleterious. At optimal cut-off values, which had 69-98% sensitivity in detecting GT mutations, between 27% and 71% of the novel αIIb or β3 missense variants were predicted to be deleterious. Our data have implications for understanding the evolutionary pressure on αIIbβ3 and highlight the challenges in predicting the clinical significance of novel missense variants.

C560Rβ3 caused platelet integrin αII b β3 to bind fibrinogen continuously, but resulted in a severe bleeding syndrome and increased murine mortality

BACKGROUND AND OBJECTIVES

β(3)-Deficient megakaryocytes were modified by human β(3)-lentivirus transduction and transplantation to express sufficient levels of a C560Rβ(3) amino acid substitution, for investigation of how an activated αII b β(3) conformation affects platelets in vivo in mice.

PATIENT/METHODS

As in our previous report of an R560β(3) mutation in a patient with Glanzmann thrombasthenia, R560β(3) murine platelets spontaneously bound antibody that only recognizes activated αII b β3 bound to its ligand, fibrinogen.

RESULTS

With this murine model, we showed that αII b -R560β3 mutation-mediated continuous binding of fibrinogen occurred in the absence of P-selectin surface expression, indicating that the integrin was in an active conformation, although the platelets circulated in a quiescent manner. Remarkably, only 35% of R560β(3) 'mutant' mice survived for 6 months after transplantation, whereas 87% of C560β(3) 'wild-type' mice remained alive. Pathologic examination revealed that R560β(3) mice had enlarged spleens with extramedullary hematopoiesis and increased hemosiderin, indicating hemorrhage. R560β(3) megakaryocytes and platelets showed abnormal morphology and irregular granule distribution. Interestingly, R560β(3) washed platelets could aggregate upon simultaneous addition of fibrinogen and physiologic agonists, but aggregation failed when platelets were exposed to fibrinogen before activation in vitro and in vivo.

CONCLUSIONS

The results demonstrate that continuous occupancy of αIIb β3 with fibrinogen disrupts platelet structure and function, leading to hemorrhagic death consistent with Glanzmann thrombasthenia rather than a thrombotic state.

Abnormal whole blood thrombi in humans with inherited platelet receptor defects

To delineate the critical features of platelets required for formation and stability of thrombi, thromboelastography and platelet aggregation measurements were employed on whole blood of normal patients and of those with Bernard-Soulier Syndrome (BSS) and Glanzmann's Thrombasthenia (GT). We found that separation of platelet activation, as assessed by platelet aggregation, from that needed to form viscoelastic stable whole blood thrombi, occurred. In normal human blood, ristocetin and collagen aggregated platelets, but did not induce strong viscoelastic thrombi. However, ADP, arachidonic acid, thrombin, and protease-activated-receptor-1 and -4 agonists, stimulated both processes. During this study, we identified the genetic basis of a very rare double heterozygous GP1b deficiency in a BSS patient, along with a new homozygous GP1b inactivating mutation in another BSS patient. In BSS whole blood, ADP responsiveness, as measured by thrombus strength, was diminished, while ADP-induced platelet aggregation was normal. Further, the platelets of 3 additional GT patients showed very weak whole blood platelet aggregation toward the above agonists and provided whole blood thrombi of very low viscoelastic strength. These results indicate that measurements of platelet counts and platelet aggregability do not necessarily correlate with generation of stable thrombi, a potentially significant feature in patient clinical outcomes.

A mutation in the β3 cytoplasmic tail causes variant Glanzmann thrombasthenia by abrogating transition of αIIb β3 to an active state

BACKGROUND

The cytoplasmic tails of α(IIb) and β(3) regulate essential α(IIb) β(3) functions. We previously described a variant Glanzmann thrombasthenia mutation in the β(3) cytoplasmic tail, IVS14: -3C>G, which causes a frameshift with an extension of β(3) by 40 residues.

OBJECTIVES

The aim of this study was to characterize the mechanism by which the mutation abrogates transition of α(IIb) β(3) from a resting state to an active state.

METHODS

 We expressed the natural mutation, termed 742ins, and three artificial mutations in baby hamster kidney (BHK) cells along with wild-type (WT) α(IIb) as follows: β(3) -742stop, a truncated mutant to evaluate the effect of deleted residues; β(3) -749stop, a truncated mutant that preserves the NPLY conserved sequence; and β(3) -749ins, in which the aberrant tail begins after the conserved sequence. Flow cytometry was used to determine ligand binding to BHK cells.

RESULTS AND CONCLUSIONS

Surface expression of α(IIb) β(3) of all four mutants was at least 60% of WT expression, but there was almost no binding of soluble fibrinogen following activation with activating antibodies (anti-ligand-induced-binding-site 6 [antiLIBS6] or PT25-2). Activation of the α(IIb) β(3) mutants was only achieved when both PT25-2 and antiLIBS6 were used together or following treatment with dithiothreitol. These data suggest that the ectodomain of the four mutants is tightly locked in a resting conformation but can be forced to become active by strong stimuli. These data and those of others indicate that the middle part of the β(3) tail is important for maintaining α(IIb) β(3) in a resting conformation.

Characterization of the cDNA and genomic DNA sequence encoding for the platelet integrin alpha IIB and beta III in a horse with Glanzmann thrombasthenia

Glanzmann thrombasthenia (GT) is characterized by a defect of platelet aggregation. This autosomal recessive genetic disorder is caused by an abnormality of the platelet glycoprotein receptors alpha IIb or beta III. Recently, we identified a horse with clinical and pathological features of GT. The aim of this study was to describe this case of GT at the molecular level. A point mutation from G to C in exon 2 of ITGA2B causing a substitution of the expected amino acid arginine 72 (Arg(72)) by a proline (Pro(72)) was encountered. This amino acid change may result in abnormal structural conformations that yield an inactive alpha IIb subunit. The genomic DNA analysis showed that this horse was homozygous for the missense mutation.

An αIIb mutation in patients with Glanzmann thrombasthenia located in the N-terminus of blade 1 of the β-propeller (Asn2Asp) disrupts a calcium binding site in blade 6

BACKGROUND

Studies of Glanzmann thrombasthenia (GT)-causing mutations has generated invaluable information on the formation and function of integrin αIIbβ(3).

OBJECTIVE

To characterize the mutation in four siblings of an Israeli Arab family affected by GT, and to analyze the relationships between the mutant protein structure and its function using artificial mutations.

METHODS AND RESULTS

Sequencing disclosed a new A97G transversion in the αIIb gene predicting Asn2Asp substitution at blade 1 of the β-propeller. Alignment with other integrin α subunits revealed that Asn2 is highly conserved. No surface expression of αIIbβ(3) was found in patients' platelets and baby hamster kidney (BHK) cells transfected with mutated αIIb and WT β(3). Although the αIIbβ(3) was formed, the mutation impaired its intracellular trafficking. Molecular dynamics simulations and modeling of the αIIbβ(3) crystal indicated that the Asn2Asp mutation disrupts a hydrogen bond between Asn2 and Leu366 of a calcium binding domain in blade 6, thereby impairing calcium binding that is essential for intracellular trafficking of αIIbβ(3). Substitution of Asn2 to uncharged Ala or Gln partially decreased αIIbβ(3) surface expression, while substitution by negatively or positively charged residues completely abolished surface expression. Unlike αIIbβ(3), αVβ(3) harboring the Asn2Asp mutation was surface expressed by transfected BHK cells, which is consistent with the known lower sensitivity of αVβ(3) to calcium chelation compared with αIIbβ(3).

CONCLUSION

The new GT causing mutation highlights the importance of calcium binding domains in the β-propeller for intracellular trafficking of αIIbβ(3). The mechanism by which the mutation exerts its deleterious effect was elucidated by molecular dynamics.

Atomic force microscopy-based molecular recognition of a fibrinogen receptor on human erythrocytes

The established hypothesis for the increase on erythrocyte aggregation associated with a higher incidence of cardiovascular pathologies is based on an increase on plasma adhesion proteins concentration, particularly fibrinogen. Fibrinogen-induced erythrocyte aggregation has been considered to be caused by its nonspecific binding to erythrocyte membranes. In contrast, platelets are known to have a fibrinogen integrin receptor expressed on the membrane surface (the membrane glycoprotein complex alpha(IIb)beta(3)). We demonstrate, by force spectroscopy measurements using an atomic force microscope (AFM), the existence of a single molecule interaction between fibrinogen and an unknown receptor on the erythrocyte membrane, with a lower but comparable affinity relative to platelet binding (average fibrinogen--erythrocyte and --platelet average (un)binding forces were 79 and 97 pN, respectively). This receptor is not as strongly influenced by calcium and eptifibatide (an alpha(IIb)beta(3) specific inhibitor) as the platelet receptor. However, its inhibition by eptifibatide indicates that it is an alpha(IIb)beta(3)-related integrin. Results obtained for a Glanzmann thrombastenia (a rare hereditary bleeding disease caused by alpha(IIb)beta(3) deficiency) patient show (for the first time) an impaired fibrinogen--erythrocyte binding. Correlation with genetic sequencing data demonstrates that one of the units of the fibrinogen receptor on erythrocytes is a product of the expression of the beta(3) gene, found to be mutated in this patient. This work demonstrates and validates the applicability of AFM-based force spectroscopy as a highly sensitive, rapid and low operation cost nanotool for the diagnostic of genetic mutations resulting in hematological diseases, with an unbiased functional evaluation of their severity.

Identification of compound heterozygous mutations in the ITGA2B gene in a Chinese patient with Glanzmann thrombasthenia

BACKGROUND

Glanzmann thrombasthenia (GT) is an autosomal recessive bleeding disorder characterized by the tendency to hemorrhage and the inability of platelets to aggregate in response to agonists. GT is caused by a defect of the platelet glycoprotein IIb/IIIa complex. The objective of this study was to describe the clinical features and the genetic cause of GT in a 6-year-old girl from south China.

METHODS

A three-generation family was studied. The proband patient aged 6 years and her parents undertook examinations of platelet counts, blood film, bleeding time, platelet aggregation, and flow cytometry. All coding exons of the ITGA2B and ITGB3 genes were amplified by polymerase chain reaction (PCR), and direct sequencing was performed for mutational screening on the patient and normal controls consisted of 52 healthy blood donors. Reverse transcription PCR was conducted to test for exon skipping.

RESULTS

The proposita patient showed dispersing platelets, prolonged bleeding time, and severely reduced platelet aggregation in response to the physiological agonists adenosine diphosphate (ADP), epinephrine, collagen, and ristocetin. Flow cytometric measurements showed that the contents of alphaIIb and beta3 were significantly decreased. Sequencing results demonstrated two different types of heterozygous mutations existed in the alphaIIb gene (c.2930delG and IVS15-1delG). The compound mutations were also confirmed in the patient's mother and father separately.

CONCLUSIONS

The alphaIIbbeta3 deficiency of the proband was caused by two compound ITGA2B mutations, which were first reported in Chinese GT patients. The IVS15-1delG was first confirmed to cause an exon skipping.

[Inherited bleeding disorders common in Jews]

Four inherited disorders of hemostasis have been identified in Jews with a relatively high frequency: Factor XI deficiency, factor VII deficiency, combined factor V and VIII deficiency and GLanzmann thrombasthenia. During the past decades, the bleeding manifestations of these disorders, the diagnosis, the molecular-genetic basis and therapy have been discerned. Furthermore, the prevalence of the respective mutant genes have been delineated in various Jewish Communities. Each one of the disorders can serve as a model enabling better understanding of the pathophysioLogy of the coagulation systems. On the basis of data obtained from the research of Glanzmann thrombasthenia, several widely used drugs have been developed as effective antithrombotic agents.

The study of the Golgi apparatus in blood--basic science and clinical applications

The Golgi apparatus (GA) is a cytoplasmic organelle that is of great interest to all scientists for its key role in the biosynthesis, transporting and sorting of both lipids and proteins located at the intersection of the secretory and endocytic pathways. Recently, more and more evidence shows that changes in the Golgi apparatus play an important role in the clinical progression and pathological development of many diseases. In this review, we will summarize the alteration of the Golgi apparatus in blood cells and anti-Golgi complex antibodies in blood serum under different conditions and further clarify the contribution of the Golgi apparatus dysfunction to the course of these diseases and its pathophysiological basis, which will significantly improve our understanding and impact our ability to develop more effective therapies for these diseases.

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.

Mutations in the β3 gene giving rise to type I Glanzmann thrombasthenia in two families in Portugal

Glazzmann thrombasthenia is an inherited bleeding syndrome in which an absence of platelet aggregation is associated with quantitative or qualitative deficiencies of the alphaIIbbeta3 integrin. We now describe biochemical and molecular studies on two Portuguese families where platelets lack both surface and intracellular pools of alphaIIbbeta3. DNA extraction was followed by PCR-SSCP analysis of all exons and intronic boundaries in the alphaIIb and beta3 genes. Migration abnormalities were found for PCR fragments encompassing exon 12 (family 1) and exon 10 (family 2). For patient 1, there was a homozygous G to T transition at position 1846 which resulted in a stop codon at codon 616 in the beta3 gene. For patient 2, direct sequencing revealed a homozygous 1347C insert which led to a stop codon at codon 444 in the beta3 gene. For both patients a single mutated allele was inherited from each parent. Evidence is accumulating that nonsense mutations leading to a truncated beta3 may be a frequent cause of type I Glanzmann thrombasthenia in the Iberian peninsula.

Glanzmann's thrombasthenia: an overview

Glanzmann's thrombasthenia (GT) is an autosomal recessive inherited bleeding disorder due to a defect in platelet function. The hallmark of this disease is severely reduced/absent platelet aggregation in response to multiple physiological agonists. Bleeding signs in GT include epistaxis, bruising, gingival hemorrhage, gastrointestinal hemorrhage, hematuria, menorrhagia, and hemarthrosis. Homozygous or compound heterozygous mutations in the genes of GPIIb and GPIIIa lead to GT. A patient with GT, with no possible causative mutations in GPIIb and GPIIIa genes, may harbor defects in a regulatory element affecting the transcription of these 2 genes. GT occurs in high frequency in certain ethnic populations with an increased incidence of consanguinity such as in Indians, Iranians, Iraqi Jews, Palestinian and Jordanian Arabs, and French Gypsies. Carrier detection in GT is important to control the disorder in family members. Carrier detection can be done both by protein analysis and direct gene analysis.

The GPIIb/IIIa (integrin alphaIIbbeta3) odyssey: a technology-driven saga of a receptor with twists, turns, and even a bend

Starting 90 years ago with a clinical description by Glanzmann of a bleeding disorder associated with a defect in platelet function, technologic advances helped investigators identify the defect as a mutation(s) in the integrin family receptor, alphaIIbbeta3, which has the capacity to bind fibrinogen (and other ligands) and support platelet-platelet interactions (aggregation). The receptor's activation state was found to be under exquisite control, with activators, inhibitors, and elaborate inside-out signaling mechanisms controlling its conformation. Structural biology has produced high-resolution images defining the ligand binding site at the atomic level. Research on alphaIIbbeta3 has been bidirectional, with basic insights resulting in improved Glanzmann thrombasthenia carrier detection and prenatal diagnosis, assays to identify single nucleotide polymorphisms responsible for alloimmune neonatal thrombocytopenia, and the development of alphaIIbbeta3 antagonists, the first rationally designed antiplatelet agents, to prevent and treat thrombotic cardiovascular disease. The future looks equally bright, with the potential for improved drugs and the application of gene therapy and stem cell biology to address the genetic abnormalities. The alphaIIbbeta3 saga serves as a paradigm of rigorous science growing out of careful clinical observations of a rare disorder yielding both important new scientific information and improved diagnosis, therapy, and prevention of other disorders.

[Molecular mechanisms of Glanzmann thrombasthenia caused by alpha II b L721R and Q860X compound heterozygous mutation]

OBJECTIVE

To explore the molecular mechanisms of Glanzmann thrombasthenia caused by alpha II b L721R and Q860X compound heterozygous mutation.

METHODS

All exons and exon-intron boundaries of alpha II b and beta3 gene were amplified by PCR and analyzed by direct DNA sequencing. Gene polymorphisms were excluded by direct DNA sequencing. Alpha II b L721R and Q860X mutants expressing vectors were constructed by in vitro site-directed mutagenesis. The expression of alpha II b L721R and Q860X mutants on transfected cell membrane were analyzed by flow cytometry and the whole expression level was confirmed by Western blot. The subcellular localizations of alpha II b L721R and Q860X mutants were determined by immunofluorescent confocal scanning microscopy.

RESULTS

The alpha II b compound heterozygous mutations, T2255G (L721R) and C2671T (Q860X), were identified in the proband, the former being inherited from the maternal side and the latter the paternal side. The 293T cells cotransfected with mutated alpha II b L721R and wild-type beta3 expression plasmids expressed 2.1% of normal amount of alpha II b on the cell surface as shown by FACS, in contrast to 31.9% of normal amount of alpha II b on the cells cotransfected with cDNAs of mutated alpha II b Q860X and wildtype beta3 expression plasmids. Western blot of the cell lysates showed no detectable mature alpha II b in cells lysates with L721R mutant. While, truncated alpha II b protein was detected in cell lystes with Q860X mutant. Immunofluorescence studies demonstrated that both L721R and Q860X mutant pro-alpha II bbeta33 complex colocalized in endoplasmic reticulum, but a little in Golgi.

CONCLUSIONS

The L721R and Q860X mutations of alpha II b prevent transport of the pro-alpha II bbeta3 complex from the endoplasmic reticulum to the Golgi, hindering its maturation and surface expression. The impaired alpha II bbeta3 transport is responsible for the thrombasthenia.

[Glanzmann's thrombasthenia: first case descriptions in sub-Saharan Africa]

BACKGROUND

Constitutive hemorrhagic diseases that affect primary haemostasis are reportedly rare in sub-Saharan Africa.

AIM

This study arrived to report within a Congolese family five cases of Glanzmann's thromboasthenia.

PATIENT

5 cases of the congenital form of Glanzmann's thromboasthenia were depicted in a Congolese family. The disease was first discovered with a young student who was transferred in France, who had shown a tendency to develop hemorrhages since childhood. This tendency was enhanced following abdominal surgery to treat peritonitis. Like the other 3 cases, she had a prolonged bleeding time, albeit with normal von Willebrand factor plasma values. A 7 year old girl died following appendectomy from post-surgery hemorrhages. In this young patient, platelet aggregation could be induced only by ristocetine, all other conventional agonists failed. Flow cytometric analysis showed the total absence of GPIIbIIIa. The hemorrhages in the girls could be managed by cyclic administration of oestrogens and iron supplementation. Serologic analysis showed this patient to be positive for hepatitis C virus antibodies.

CONCLUSION

This first description of Glanzmann's thrombo-asthenia in Blacks in sub-Saharan Africa shows the necessity of establish inter-hospital cooperation for the improvement of the management of constitutive hemorrhagic diseases in the Hematology wards.