in Saudi Arabia Prof. Layla A. M. Bashawri Imam Abdulrahman Bin - - PowerPoint PPT Presentation

Glanzmann Thrombasthenia in Saudi Arabia

• Prof. Layla A. M. Bashawri

Imam Abdulrahman Bin Faisal University

• Named after the Swiss Pediatrician Eduardo Glanzmann in 1918 who

described bleeding symptoms associated with a normal platelet count, (“weak platelets”) described as hereditary hemorrhagic thrombasthenia.

• Glanzmann thrombasthenia is a bleeding disorder marked by

prolonged bleeding time, normal platelet count and absence of platelet aggregation in response to platelet agonists ADP, collagen, arachidonic acid and thrombin, impaired or absent clot retraction.

• Transmitted as an autosomal recessive trait with consanguinity

reported and intercommunity marriages in affected patients.

INTRODUCTION

• Platelets from GT patients show quantitative or qualitative

abnormalities of platelet membrane glycoprotein (GP) IIb–IIIa complex, also called integrin IIb3, which mediates aggregation

• f activated platelets.
• GPIIb/IIIa (IIb and 3) subunits are prominent integral

components of the platelet membrane that form heterodimers containing specific sites for platelet cohesion.

• The IIb3 integrin serves as a platelet receptor for fibrinogen,

fibronectin, vitronectin and VWF.

PATHOGENESIS

Classification of Glanzmann Thrombasthenia

Type I Disease Patients with no platelet aggregation, absent or severely deficient fibrinogen binding, absent clot retraction and platelet GP IIb/IIIa levels < 5%. Type II Disease Patients with no platelet aggregation, fibrinogen binding present, normal or moderately deficient clot retraction and GP IIb/IIIa levels in the 10– 20% range. Variant Disease Patients with no or very abnormal aggregation but in most cases with GPIIb or GP IIIa gene defects allowing GPIIb/IIIa expression more than 50%, variable fibrinogen binding and clot retraction.

Molecular Biology

The two genes encoding GPIIb (ITGA2B) and GPIIIa (ITGB3) are closely associated at chromosome 17q21. The GT associated mutations that have been identified at the molecular level has substantially increased in recent years enabling the development of an Internet database (GT Database). Inherited genetic mutations in ITGA2B, ITGB3 result in a heterogeneity of the Thrombasthenia phenotypes.

Molecular Biology

These defects have been shown to lead to disruption of GPIIb / IIIa synthesis, receptor assembly and / or function. Leading to prevention of GPIIb / IIIa from binding to its major adhesive ligands VWF and Fibrinogen to mediate platelet aggregation.

• To date more than 100 distinct genetic defects have been

described ranging from point mutations, small deletions and insertions to large deletions and inversions occurring with even distribution on both genes.

Molecular Biology

First Molecular Analysis of ITGB3 gene in Saudi Arabia (Tarek Owaidah et al) 1 novel germline mutation in exon 13, results in premature stop codon and protein truncation. Blood 2011,118:1136

Genetic Basis

Incidence:

• Rare worldwide, (reported incidence 1/1000,000),occurs in regions

where consanguineous marriages are common, groups of patients have been identified. e.g. India, Iraqi-Jews and Arabs in Palestine, and in Jordan and Saudi Arabia.

In Saudi Arabia:

• A previous report from our institution in 1988 revealed a high

incidence of this disorder in the EP (12/34). (This makes it probably the second hemorrhagic disorder to HA in EP).

• A study in Riyadh in 1995-96, 18/168. (where it was the 3rd H.BD).

even type II reported in 1990.

• 1997 (16 Saudi patients over 11 years EP).

Madinah:

(24 over 16 years 1992 – 2008) Tarawah A.

Saudi Arabia

Riyadh 44 patients (R. Alnounou 2005-2009). GT1-34, GT2-6, GT3-4. Riyadh 2011 , 51 patients for Molecular Analysis. Tarek Owaidah etal

• Easy and spontaneous bruising.
• Mucous membrane bleeding.
• Subcutaneous hematomas
• Petechiae uncommon, but purpura and ecchymoses may be striking
• Rare hemarthrosis
• Fatal hemorrhages
• Clinical heterogeneity, an extreme variability in the clinical symptoms

CLINICAL FEATURES

Clinical Severity

• GT

is certainly a severe hemorrhagic disease nevertheless bleeding, severity is unpredictable.

• Emphasized by the inconsistency between siblings who

presumably share the same genetic defect.

Diagnosis and Lab. Investigations

The condition shares common clinical and laboratory features as with other platelet disorders. Careful analysis of the medical history and family history. CBC, PBS, PT, aPTT

Platelet Count: N,PBS: MPV:N BT usually markedly prolonged. Tests of platelet functions:

Platelet aggregation:

ADP, epinephrine, thrombin, AA, Collagen, No  aggregation Ristocetin  aggregation. (subnormal in our cases) Clot retraction: absent or reduced (rarely normal)

DIAGNOSIS AND LAB. INVESTIGATIONS

• PFA highly sensitive test. The PFA assay is prolonged among

patients with GT.

• Flow cytometry can be beneficial, under flow cytometric

analysis CD41 and CD 61 are markedly decreased or absent.

DIAGNOSIS

• Flow cytometry is the current method of choice for confirmation of

the diagnosis procedures exist both for quantitative assessment of the residual GPIIb/IIIa content of platelets and for testing the inability of variant GT; GPIIb/IIIa to express activation- dependent epitopes (recognized by the absence of binding of monoclonal antibodies such as PAC-I or FITC- fibrinogen ).

The best way to diagnose GT is through mutation analysis. Genomic DNA sequencing of the 45 exons comprising the IIb- 3 unit, along with the splice sites of the ITGB3 and ITGA2B gene, should be investigated, and the established mutations be confirmed with a second DNA sample analysis.

DIAGNOSIS

By Laboratory Tests: Mainly: VWD: VIII assay, VWF, PFT BSS: Platelet count, PBS, PFT Afibrinogenaemia: same PFT but muscle haemorrhages, intra- abdominal hemorrhages, fetal wastage, PT, PTT, TT, fibrinogen level.

DIFFERENTIAL DIAGNOSIS

• Overall, the diagnosis of GT includes presence of a normal

platelet count, absent platelet aggregation in response to all physiologic stimuli (is pathognomonic for GT), and abnormal clot retraction is rarely observed in other disorders.

• Prolonged bleeding time and PFA time.

• In this study 31 patients were diagnosed with Glanzmann

thrombasthenia. (Retrospective review from Coagulation laboratory, Hematology Clinic, medical records department).

• Clinical data, family history were recorded.
• Laboratory Investigations included CBC, PBS, bleeding time,

APTT, PT, Clot Retraction and Platelet Aggregation.

• In some of our patients flow cytometric analysis of platelet

glycoproteins was carried out.

Eastern Province Study (KFHU)

• 31 Patients, 17 males, 14 females, were Saudi patients (most

from eastern province and from the southern part of the Kingdom).

• Positive history of first degree consanguinity was observed and

there was a positive family history also.

RESULTS

Patient Age now Gender Age at Clinical Presentation (Years) Presentation

1. 55 M early childhood Gum bleeding, bled at circumcision, hemarthrosis 2. 28 M 1 year Epistaxis, bruises 3. 26 M 20 days Bled at circumcision; Haemoarthrosis Bruises 4. 31 M 2 years old Buccal mucosa / Melena, epistaxis, bruises, chronic gum bleeding 5. 23 M early childhood Epistaxis; Bruises

Summary: Clinical Features

Patient Age now Gender Age at Clinical Presentation (Years) Presentation

6. 22 M early childhood Epistaxis 7. 25 M 11 months Bruises, blunt injury to Right eye. 8. 21 M 1-1/2 Because of prolonged BT before Circumcision 9. 18 F 1 month Petchial rash at 1 month, bleeding with tooth eruption, hemoptysis with cough (URTI) 10. 18 F 9 months Gum bleeding

Summary: Clinical Features

Patient Age now Gender Age at Clinical Presentation (Years) Presentation

11. 54 M 7 years Circumcision bleeding, Epistaxis, Hematuria, Rectal bleeding 12. 37 F 4 years Epistaxis, Menorrhagia, GIT bleeding, Petechial, Ecchymosis, Haemoarthrosis, 13. 35 F early childhood Uncontrolled menorrhagia, gum bleeding, delayed wound healing 14. 38 F 7 years Melena; menorrhagia; rectal bleeding; gum bleeding; epistaxis; haemoarthrosis; Hematuria 15. 45 (died) M early childhood Severe GIT bleeding

Summary: Clinical Features

Patient Age now Gender Age at Clinical Presentation (Years) Presentation

16. 37 F early childhood Menorrhagia 17. 40 M early childhood Gum bleeding; epistaxis 18. 38 F early childhood Menorrhagia; Petechiae 19. 51 F early childhood Menorrhagia; Epistaxis 20. 81 M early childhood Epistaxis

Summary: Clinical Features

Patient Age now Gender Age at Clinical Presentation (Years) Presentation 21. 34 F early childhood Menorrhagia, bruises; gum bleeding 22. 38 M early childhood Gum bleeding 23. 39 M early childhood Epistaxis; Gum bleeding 24. 40 F early childhood Petechiae; menorrhagia 25. 36 F early childhood Epistaxis

Summary: Clinical Features

Patient Age now Gender Age at Clinical Presentation (Years) Presentation 26. 37 F early childhood Menorrhagia; epistaxis 27. 35 M early childhood Gum bleeding; Epistaxis 28. 35 M early childhood Epistaxis 29. 46 (Died) F 5 years Severe GIT bleeding, Menorrhagia 30. 40 M early childhood Epistaxis 31. 38 F early childhood Bruises, Menorrhagia

Summary: Clinical Features

• Pat. Sex

Clot Bleeding ADP Collagen Epinephrine Arachidonic Ristocetin Retraction Time

Acid 1. M Poor > 15 3% 9% 5% 1% 7% 2. M Normal > 15 3% 17% 2% 2% 71% 3. M Normal > 15 2% 16% 2% 1% 79% 4. M Poor > 15 3% 26% 1% 0% 64% 5. M Poor > 15 1% 11% 3% 0% 57% 6. F Nil > 15 1% 4% 3% 1% 57% 7. M Normal 10.5 9% 7% 8% 11% 67% 8. F Normal 9.0 4% 21% 5% 7% 85%

LABORATORY FINDINGS

• Pat. Sex

Clot Bleeding ADP Collagen Epinephrine Arachidonic Ristocetin Retraction Time

Acid 9. M Poor > 15 2% 16% 3% 1% 46% 10. M Poor > 15 2% 7% 1% 1% 35% 11. F Poor > 15 3% 11% 0% 0% 16% 12. M Nil > 15 18% 1% 2% 58% 62% 13. M Poor > 15 2% 0% 2% 0% 33% 14. F Nil > 15 2% 30% 2% 3% 54% 15. F Normal > 15 30% 26% 6% 25% 35%

LABORATORY FINDINGS

• Pat. Sex

Clot Bleeding ADP Collagen Epinephrine Arachidonic Ristocetin Retraction Time

Acid 16. M Normal > 15 1% 20% 3% 2% 36% 17. F Poor > 15 0% 17% 0% 0% 61% 18. M Poor > 15 4% 48% 4% 6% 77% 19. M Poor > 15 3% 56% 6% 0% 71% 20. M Poor > 15 8% 0% N/A 62% 25% 21. F Nil > 15 7% 21% 2% 0% 60% 22. F Nil > 15 9% 13% 9% 2% 39% 23. F Nil > 15 6% 5% 4% 7% 84%

LABORATORY FINDINGS

• Pat. Sex

Clot Bleeding ADP Collagen Epinephrine Arachidonic Ristocetin Retraction Time

Acid 24. M Nil > 15 6% 17% 7% 0% 30% 25. F Poor > 15 3% 19% 2% 4% 35% 26. F Nil > 15 2% 18% 3% 8% 43% 27. F Nil > 15 2% 20% 2% 4% 16% 28. M Poor > 15 0% 18% 0% 2% 14% 29. M Nil > 15 0% 16% 0% 1% 1% 30. F Nil > 15 1% 8% 2% 1% 62% 31. F Nil > 15 35% 36% 33% 35% 46%

LABORATORY FINDINGS

• Plt. Antigen

Control Patient CD42a 83% 99% CD42b 97% 98% CD61 91% 40% CD62 46% 18% CD62p 25% 29% CD41a 98% 0%

FCM ANALYSIS OF PLATELET GLYCOPROTEINS

• Plt. Antigen

Control Patient Pt’s Sister CD42a 83% 70% 86% CD42b 97% 26% 42% CD61 91% 63% 95% CD62 46% 9% 47% CD62p 25% 24% 63% CD41a 70% 17% 22%

• Platelet transfusions for bleeding episodes and before invasive

procedures (even in patients with minimal past hemorrhagic symptoms). Neither clinical history nor biologic tests can adequately predict the bleeding risk. The potential risk of platelet alloimmunization by HLA antigens and isoantibodies against GPIIb/IIIa because they considerably worsen therapeutic management and prognosis.

• Antifibrinolytic drugs.
• Desmopression in some patients with variable success.

Management

• DDAVP acts by inducing the release of VWF and tPA

from endothelium and plasma levels of FVIII increase. The relevance of this on GT is unclear. ? VWF – GPIb interaction enhanced and platelet interaction with fibrin. Infusion of rFVIIa (Novoseven, Novo NorDisk ) is now

• ften used to stop bleeding in GT especially patients

with isoantibodies, invasive procedures and severe bleeding in children. rVIIa enhances deposition of platelets to vessel wall and restores an aggregation response by stimulating TF independent thrombin generation and fibrin formation.

Management

Preventive Measures + treatment:

• Dental hygiene
• Antiplatelet therapy must be avoided.
• Iron and Folate supplement
• Hormonal therapy: ♀ (before menarche)
• Antifibrinolytic agents
• Gingival bleeding, tooth extraction

: autologous fibrin glue, local.

MANAGEMENT

Preventive Measures + treatment:

• Erythropoietin
• BMT: allogeneic
• Gene Therapy
• Antibody removal

Prognosis: Severe disease but generally good survival

• Local measures (packs, gelatin sponge or gauze soaked in topical thrombin).
• Embolic occlusions of vessels etc.
• Oral norethisterone.
• Menstrual bleeding high doses of progesterone, OCP, Packing uterine cavity.
• Iron deficiency Anemia ! Iron supplements especially in infants and adolescents.
• Plasma exchange can restore efficacy of platelet concentrates by temporally

removing the antibody , cumbersome and specialized treatment that only a few centers can provide.

• Drugs like Aspirin interfering with platelet function are contraindicated.

Management

Acquired Thrombasthenia

• A disorder identical to GT can be acquired through an

autoantibody that inhibits the fibrinogen receptor function of platelet GPIIb/IIIa. Multiple myeloma, Evan's Syndrome, lymphoproliferative disease, APL.

• Treatment of patients with anti GPIIb/IIIa drugs; abciximab,

tirofiban etc.

Prognosis

• A severe hemorrhagic disease, prognosis is excellent with

careful supportive care.

• Mortality rare, will decrease further, as early diagnosis becomes

common.

• BM transplantation.
• GT a suitable disease for gene therapy?

• Main problem we face regarding the goals below is the

patients refusing frequent blood work up and family studies.

• Patient / family education especially in relation to nature of

the disease, marriage counseling, investigations, vaccination and early management including importance of HLA – matched platelets from the start is needed.

• Importance of the role of a National registry for GT as well as
• ther bleeding disorders.
• More studies and collaboration needed, true Incidence in

KSA, Gulf region. Molecular Analysis.

CONCLUSION AND RECOMMENDATIONS