Glanzmann thrombasthenia

Clinical Presentation

Glanzmann thrombasthenia is an autosomal recessive bleeding disorder characterized by failure of platelet aggregation and by absent or reduced clot retraction. The disorder results from quantitative or qualitative abnormalities of the GPIIb/IIIa platelet surface fibrinogen receptor complex due to mutations in the ITGA2B (GPIIb) or ITGB3 (GPIIIa) genes. The disorder is apparent soon after birth with episodic mucocutaneous bleeding and unprovoked bruising. Epistaxis is common and women experience menorrhagia. Intracranial bleeding may also occur. Platelet counts, morphology and coagulation times are normal. Platelets fail to aggregate, either spontaneously or in response to agonists including ADP, thrombin, or epinephrine, although there may be a transient ristocetin response.

Indications for Testing

Diagnostic testing to confirm a clinical diagnosis of Glanzmann thrombasthenia.

Testing in relatives of an affected individual for clinical management and genetic counselling. These referrals require that the pathogenic mutation(s) have been identified in the index case.

Prenatal diagnosis

Utility

Sequencing of the protein-coding regions is expected to detect >90% of disease alleles in individuals with an inherited deficiency.

Specimen Requirements

Venous blood (2-5ml K-EDTA, not to be frozen prior to or during transport)

Genomic DNA (approximately 5μg)

Specimen containers and referral forms must be labelled with at least two corresponding unique identifiers.

Turnaround time

Approximately 8 weeks (40 working days) from receipt of sample. A priority service may be available for urgent referrals at an additional cost, please contact the laboratory for further information.

Patient Consent

Referrals must generally be made from the Clinical Genetics services or appropriate clinical specialist. It is assumed that informed consent for genetic testing has been obtained from the patient or their parent/guardian and that the implications of a positive result for other family members have been discussed.

NGS of ITGAT2B & ITGB3 exons 1-30 & 1-15 (entire coding region)

Glanzmann thrombasthenia Diagnostic Test

Glanzmann thrombasthenia Diagnostic Test

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