Wiskott-Aldrich Syndrome (WAS)
Wiskott-Aldrich syndrome (WAS) is an X-linked syndrome that presents most commonly with abnormal bleeding, petechiae and low platelet counts. The platelet size is typically very small (<6.0 fl). (Note: Some automated counters used in clinical labs disregard the small platelets in WAS as debris and overestimate the platelet size.) Other clinical manifestations in WAS include eczema, immunodeficiency and susceptibility to infections, autoimmunity (usually autoimmune hemolytic anemia or thrombocytopenia) and malignancy (lymphomas).
X-Linked Thrombocytopenia (XLT)
X-linked thrombocytopenia (XLT) is a milder disease than WAS and is characterized by thrombocytopenia and small platelets without the associated immune deficiency, eczema, etc. It is typically caused by point mutations in WASP that allow expression of a partially functional WASP protein.
X-Linked Congenital Neutropenia (XLN)
X-linked congenital neutropenia (XLN) is a much milder disease than WAS and is characterized by chronic or intermittent neutropenia without platelet problems, immune deficiency or eczema. It is caused by mutations in the GTPase-binding domain of WASP that cause the protein to be in a constitutively active state.
Key Clinical Features
- Abnormal bleeding: Petechiae, easy bruising, bleeding at mucosal surfaces/after circumcision
- Thrombocytopenia: Low platelet counts and small platelet size
- Eczema: Usually moderate to severe
- Immune deficiency with frequent infections: Otitis media, bronchitis,
Molecular Defects Associated with WAS
- (Wiskott-Aldrich syndrome)
Suggested Testing Approach
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- Flow cytometry: Peripheral Blood Mononuclear Cells (PBMCs) are evaluated by multiparameter flow cytometry for intracellular expression of WASP protein in lymphocytes.
- Gene sequencing: All exons (1 to 12) are evaluated by bidirectional sequencing from genomic DNA. Sequencing includes all exon/intron boundaries.
Testing Packet for WAS
Sample Submission Form, Available Tests and Sample Requirements/Shipping Instructions