Molecular testing to distinguish von Willebrand disease (VWD) type 2B from pseudo (platelet-type) VWD.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA) or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Mild to moderate mucocutaneous bleeding after brushing or flossing teeth, unexplained bruising, prolonged repeated nosebleeds, menorrhagia, and prolonged bleeding following childbirth, trauma or surgery. Thrombocytopenia may be present and worsen during the stress of severe infection, surgery or pregnancy.
Incidence: Very rare.
Inheritance: Autosomal dominant.
Cause: Pathogenic GP1BA mutations.
Clinical Sensitivity: Unknown.
Methodology: Targeted bidirectional sequencing of the GP1BA gene mutations c.746G>T (p.Gly249Val), c.746G>A (p.Gly249Ser), and c.763A>G (p.Met255Val); PCR followed by fragment analysis of c.1306del27 (p.436_444del9).
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations, and large deletions/duplications will not be detected. GP1BA mutations other than the four targeted, will not be evaluated.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2005477||VWD Platelet Type (GP1BA) Seq Spcm|
|2005478||VWD PlatletType (GP1BA) Seq Interp|
- GP1BA Sequencing
- Platelet Type Von Willebrand Disease (vWD)
- Pseudo Von Willebrand Disease (vWD)
- Von Willebrand Disease (vWD) Platelet Type
- VWD Platelet Type 4