Elsevier

Blood Reviews

Volume 21, Issue 1, January 2007, Pages 21-36
Blood Reviews

Review
The gray platelet syndrome: Clinical spectrum of the disease

https://doi.org/10.1016/j.blre.2005.12.003Get rights and content

Summary

The gray platelet syndrome (GPS) is a rare inherited disorder of the megakaryocyte (MK) lineage. Thrombocytopenia and enlarged platelets are associated with a specific absence of α-granules and their contents. GPS patients exhibit much heterogeneity both in bleeding severity and in their response to platelet function testing. A unique feature is that proteins endogenously synthesised by megakaryocytes (MK) or endocytosed by MK or platelets fail to enter into the secretable storage pools that characterise α-granules of normal platelets. Although the molecular basis of the disease is unknown, evidence suggests that α-granules simply fail to mature during MK differentiation. One result is a continued leakage of growth factors and cytokines into the marrow causing myelofibrosis. While for some patients platelet function may be only moderately affected, for others thrombin and/or collagen-induced platelet aggregation is markedly modified and an acquired lack of the GPVI collagen receptor has been reported. In this review, we document the clinical and molecular heterogeneity in GPS, a unique disease of the biogenesis of platelet α-granules and of the storage of growth factors and secretable proteins.

Introduction

Raccuglia1 is generally recognised to have first described the gray platelet syndrome (GPS), although earlier reports described patients with platelets that may have been symptomatic of it.2, 3, 4 A rare disease of platelets and megakaryocytes (MK), GPS is characterised by mild to moderate thrombocytopenia and the presence of large morphologically abnormal platelets lacking α-granules and their constituents. The platelets show a unique ghost-like and gray appearance on May-Grünwald-Giemsa stained blood smears. GPS is also known as α-storage pool disease (α-SPD).5 The associated bleeding syndrome is usually mild to moderate but can be severe. Current data suggests that the basic defect concerns α-granule biogenesis. Proteins that would normally be stored in these organelles are spontaneously released from MKs into the marrow. Bone marrow fibrosis is the consequence for many patients. GPS has yielded information on the function of α-granules, it has also helped characterise the storage protein pool of platelets (recently called the secretome).6

Section snippets

Seminal reports on patients with GPS

Major case reports and associated studies on patients or families that have contributed to the definition of GPS are first serially reviewed. Common findings for these patients are compared in Table I. Raccuglia1 originally described a young American boy with petechiae, a bruising tendency, and recurrent knee pain presumably from intra-articular bleeding (case 1 in Table I). Thrombocytopenia (35,000/μL and 65,000/μL on first examinations) was noted and an immune cause was suspected.

A French family with GPS and autosomal dominant inheritance

In this review, we will illustrate characteristics of GPS by reference to case 13 and to a previously unreported family where the disease appears to represent the second report (see case 10) of autosomal dominant inheritance. The patients, an adult woman (case 19), and her elderly father (case 20, now deceased) have been followed by us for many years. Members of a large French gypsy family, they both presented with thrombocytopenia (case 19: her platelet count currently ranges from 51–90 G/L),

Ultrastructure of gray syndrome platelets

EM has often been used to to confirm the diagnosis of GPS and the characteristic morphology of the platelets is shown in Fig. 1. It was the pioneering work of Breton-Gorius and her colleagues9, 10 and White7, 30 which led the way in EM studies. Results from both groups highlighted normal numbers of mitochondria, dense bodies, peroxisomes and lysosomes but few or no α-granules. Platelet morphology can be quite heterogeneous, and platelets show wide size variations. Smaller platelets tend to be

Platelet function, Ca++ stores and signaling mechanisms

Platelet aggregation in GPS has been widely studied (Table I). GPIbα-mediated platelet agglutination by ristocetin is mostly normal, but there is considerable heterogeneity between patients in the response to physiologic agonists. Aggregation by ADP in citrated PRP is normal in most reports, although it is reduced for some. There is no evidence for a decreased αIIbβ3 activation. Occasionally, all aggregations are basically normal as was the case for the Australian patients.16 Yet for many

Patient heterogeneity

The data that we have reviewed so far clearly indicates that GPS is a heterogeneous disorder. While platelets of some patients aggregate normally, other patients have a generally reduced response, for some activation by thrombin appears specifically affected while for others the response to collagen is most defective. For case 13, a much reduced aggregation with collagen was accompanied by a virtually absent expression of GPVI, as measured by flow cytometry using FITC-labeled convulxin, a

Proteins stored in α-granules

Proteins stored in α-granules and reduced in platelets of GPS patients include those synthesised in MKs such as PF4, βTG and VWF, and those endocytosed by MKs and circulating platelets such as Fg, albumin and IgG. Studies on GPS patients have helped identify proteins that are part of the storage pool. Thus osteonectin was localised to α-granules after it was found to be missing from the platelets of a GPS patient.24 Osteonectin binds to the platelet surface on release by thrombin and together

Cellular specificity

VWF is stored in the Weibel Palade bodies of endothelial cells as well as in the α-granules of MKs and platelets. This fact led Gebrone-Younés et al.46 to study the dermis capillary network in GPS, skin biopsies being taken from cases 3 and 4. Their endothelial cells normally contained VWF and P-selectin and the general morphology of the cells was normal. Falik-Zaccai et al29 also performed a skin biopsy and excluded pigmentary defects during their study of the Israeli patients.

Megakaryocytes and myelofibrosis

MK numbers are often normal in GPS despite the myelofibrosis that is seen for many patients (Table I). Like the platelets they produce, mature MKs from GPS patients are highly vacuolated. Other platelet organelles including dense bodies, catalase-containing granules and lysosomes are normally present although their distribution may be abnormal with areas of cytoplasm devoid of organelles. Smooth ER develops normally. The presence of ‘dense’ material in the distended DMS and/or vacuoles was

Other human disorders with platelet storage pool deficiency

In 1979, Weiss et al.5 showed that while many patients with ’storage pool’ disease had selective deficiencies of dense granules and their contents (δ-SPD), in others the abnormality also extended to α-granules and their stored proteins. Patients who combined dense granule defects with partial α-granule deficiencies included two families with probable autosomal dominant inheritance while a single patient of South American ancestry and with a long history of bleeding combined a severe deficiency

Potential animal models for GPS

The Wistar Furth rat was claimed to be an animal model of the GPS and indeed a deficiency of both α-granules and their contents featured in an early report.64 However, later studies highlighted an abnormal subcellular distribution of the cytoskeletal proteins, myosin and talin and defective filopodia formation.65, 66 These are abnormalities not seen in GPS. White57 and others67 subsequently failed to observe a reduced α-granule number in platelets of Wistar Furth rats, instead they highlighted

Packaging of α-granule proteins and GPS

Proteins synthesised in MKs are sorted in the trans-Golgi network. Evidence for a targeting of soluble proteins to preformed vesicles has been obtained by El.Golli et al.79 who showed that the amino acid sequence LKNG has a direct role in α-granule capture of PF4 mutants. This sequence promotes the formation of a surface-exposed hydrophilic turn/loop similar to that found in other chemokines such as RANTES. In the GPS, all evidence points to a normal production of endogenously synthesised α

Management

The bleeding tendency in GPS is basically mild to moderate although trauma-related intracranial haemorrhage has been reported in a child.85 Adult patients mostly tend to bleed at times of haemostatic stress. Platelet transfusion is the standard treatment. DDAVP (1-deamino-8-arginine vasopressin) shortened the bleeding time in a GPS patient who typically showed no detectable platelet VWF but whose plasma pool was normal.18 This implied a protective effect through an increase in plasma VWF levels

Final conclusions

GPS is a unique disease in that it allows an appreciation of the consequences of specific loss of the α-granule storage pool of proteins in platelets. Proteomics is currently revealing a whole range of new proteins in the platelet secretome.91, 92 Proteins such as calumenin, an inhibitor of the vitamin K epoxide reductase-warfarin interaction; secretogranin III, a potential monocyte chemoattractant precursor; and cyclophilin A, a vascular smooth muscle cell growth factor, are of unknown role

References (95)

  • S.P. Levine et al.

    Platelet factor 4 and the platelet secretd proteoglycan: immunologic characterization by crossed immunoelectrophoresis

    Blood

    (1990)
  • A. Drouin et al.

    Newly recognized cellular abnormalities in the gray platelet syndrome

    Blood

    (2001)
  • L. Centurione et al.

    Increased and pathologic empiripolesis of neutrophils within megakaryocytes associated with marrow fibrosis in GATA-1low mice

    Blood

    (2004)
  • A. Schmitt et al.

    Pathologic interaction between megakaryocytes and polymorphonuclear leukocytes in myelofibrosis

    Blood

    (2000)
  • H. Chagraoui et al.

    Prominent role of TGF-β1 in thrombopoietin-induced myelofibrosis in mice

    Blood

    (2002)
  • H.K. Nieuwenhuis et al.

    Patients with a prolonged bleeding time and normal aggregation tests may have storage pool deficiency: Studies on one hundred six patients

    Blood

    (1987)
  • A.T. Nurden

    Qualitative disorders of platelets and megakaryocytes

    J Thromb Haemost

    (2005)
  • B. Lo et al.

    Requirement of VPS33B, a member of the Sec1/Munc18 protein family, in megakaryocyte and platelet α-granule biogenesis

    Blood

    (2005)
  • W.H.A. Kahr et al.

    Platelets from patients with the Quebec platelet disorder contain and secrete abnormal amounts of urokinase-type plasminogen activator

    Blood

    (2001)
  • J. Breton-Gorius et al.

    A new congenital dysmegakaryopoietic thrombocytopenia (Paris-Trousseau) associated with giant platelet alpha granules and chromosome 11 deletion at 11q23

    Blood

    (1995)
  • T.I. Pestina et al.

    Abnormal subcellular distribution of myosin and talin in Wistar Furth rat platelets

    Blood

    (1995)
  • P.E. Stenberg et al.

    Prolonged bleeding time with defective platelet filopodia formation in the Wistar Furth rat

    Blood

    (1998)
  • R.T. Swank et al.

    Inherited abnormalities in platelet organelles and platelet formation and associated altered expression of low molecular weight guanosine triphosphate-binding proteins in the mouse pigment mutant gunmetal

    Blood

    (1993)
  • E.K. Novak et al.

    Inherited thrombocytopenia caused by reduced platelet production in mice with the gunmetal gene mutation

    Blood

    (1995)
  • P. Novick et al.

    The diversity of Rab proteins in vesicle transport

    Curr Opin Cell Biol

    (1997)
  • R.A. Shivdasani et al.

    Transcription factor NF-E2 is required for platelet formation independent of the actions of thrombopoietin/MGDF in megakaryocyte development

    Cell

    (1995)
  • S. Tiwari et al.

    A role for Rab27b in NF-E2-dependent pathways of platelet formation

    Blood

    (2003)
  • E.K. Novak et al.

    The regulation of platelet dense granules by Rab27a in the ashen mouse, a model of Hermansky-Pudlak and Griscelli syndromes, is granule-specific and dependent on genetic background

    Blood

    (2002)
  • L. Benit et al.

    Molecular study of the hematopoietic zinc finger gene in three unrelated families with gray platelet syndrome

    J Thromb Haemost

    (2005)
  • N. El.Golli et al.

    Evidence for α granule targeting sequence within platelet factor 4

    J Biol Chem

    (2005)
  • H.F. Heijnen et al.

    Multivesicular bodies are an intermediate stage in the formation of platelet α-granules

    Blood

    (1998)
  • P.J. Handagama et al.

    Endocytosis of fibrinogen into hamster megakaryocyte α-granules is dependent on a dimeric γA conformation

    Blood

    (1995)
  • P. Nurden et al.

    Labeling of the internal pool of GPIIb-IIIa in platelets by c7E3 Fab fragments (abciximab): flow and endocytic mechanisms contribute to the transport

    Blood

    (1999)
  • J.E. Gootenberg et al.

    Severe hemorrhage in a patient with gray platelet syndrome

    J Pediatr

    (1986)
  • J.A. Coppinger et al.

    Characterization of the proteins released from activated platelets leads to localization of novel platelet proteins in human atherosclerotic lesions

    Blood

    (2004)
  • P.B. Maguire et al.

    Application of proteomics to the study of platelet regulatory mechanisms

    Trends Cardiovasc Med

    (2004)
  • Q.X. Li et al.

    Membrane-associated forms of the beta A4 amyloid protein precursor of Alzheimer’s disease in human platelet and brain: surface expression on the activated human platelet

    Blood

    (1994)
  • G. Hemmeler

    Thrombopathie familiale

    Schweiz Med Wschr

    (1958)
  • J. Libanska et al.

    Thrombocytopénie thrombocytopathique hypogranulaire héréditaire

    Nouv Rev Fr Hématol

    (1975)
  • R. Kurstjens et al.

    Familiar thrombocytopathic thrombocytopenia

    Br J Haematol

    (1968)
  • J.M. Gerrard et al.

    Biochemical studies of two patients with the Gray Platelet syndrome. Selective deficiency of platelet alpha granules

    J Clin Invest

    (1980)
  • M.H. Ginsberg et al.

    Binding of fibronectin to α-granule-deficient platelets

    J Cell Biol

    (1983)
  • J. Breton-Gorius et al.

    Defective α-granule production in megakaryocytes from gray platelet syndrome: ultrastructural studies of bone marrow cells and megakaryocytes growing in culture from blood precursors

    Am J Pathol

    (1981)
  • S. Levy-Toledano et al.

    Gray platelet syndrome; α-granule deficiency

    J Lab Clin Med

    (1981)
  • C. Legrand et al.

    Use of a monoclonal antibody to measure the surface expression of thrombospondin following platelet activation

    Eur J Biochem

    (1988)
  • C. Legrand et al.

    Studies on platelets of patients with inherited platelet disorders suggests that collagen-induced fibrinogen binding to membrane receptors requires secreted ADP but not released α-granule proteins

    Thromb Haemost

    (1985)
  • D. Baruch et al.

    Thrombin-induced platelet factor Va formation in patients with a gray platelet syndrome

    Thromb Haemost

    (1987)
  • Cited by (191)

    • Molecular diagnostics for coagulopathies

      2023, Diagnostic Molecular Pathology: A Guide to Applied Molecular Testing, Second Edition
    • Novel manifestations of immune dysregulation and granule defects in gray platelet syndrome

      2020, Blood
      Citation Excerpt :

      All patients were thrombocytopenic, and α-granule deficiency was noted in the platelets of all cases assessed by electron or light microscopy (Figure 2A; supplemental Figure 2.1; supplemental Table 2). Consistent with previous reports,17,40,41 a wide spectrum of bleeding symptoms was reported, ranging from subcutaneous to intracranial hemorrhage. Five patients were notable for their lack of a bleeding diathesis.

    View all citing articles on Scopus
    View full text