Thrombocytopenia, X-linked

Mutations in the WAS gene have been associated with three clinical presentations: Wiskott-Aldrich syndrome and X-linked thrombocytopenia, which are associated with loss-of-function mutations, and X-linked neutropenia, which is associated with activating mutations. Wiskott-Aldrich syndrome, the most severe presentation, is classically characterized by thrombocytopenia (with small platelet size), eczema, increased susceptibility to pyogenic and opportunistic infections, and increased risk of autoimmune disease and cancer, specifically lymphomas. If untreated, this syndrome typically leads to death in early childhood or adolescence. Individuals with X-linked thrombocytopenia have thrombocytopenia (which can present intermittently), and mild or no eczema or immune deficiency. Though individuals with XLT typically have a normal lifespan, they are still at increased risk for severe disease-related complications. Individuals with XLN have a persistent neutropenia due to a promyelocyte/myelocytic maturation arrest and recurrent bacterial infections.

Tests Available

Forms and Documents

Test Details

  • Confirmation of a clinical diagnosis
  • Determination of appropriate treatment
  • Identification of at-risk family members
  • Prenatal diagnosis in at-risk pregnancies


3 weeks
2-5 mL Blood - Lavender Top Tube
Buccal Swabs | Dried Blood Spots

*Reporting times are typical, but could be extended in situations outside GeneDx's reasonable control.


  • 279.12 Wiskott-Aldrich syndrome
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**The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.


  1. Jin et al., (2004) Mutations of the Wiskott-Aldrich Syndrome Protein (WASP): hotspots, effect on transcription, and translation and phenotype/genotype correlation. Blood. 104(13): 4010-4019.
  2. Devriendt et al., (2001) Constitutively activating mutation in WASP causes X-linked severe congenital neutropenia. Nat Genet. 3:313-317.
  3. Imai et al., (2003) WASP (Wiskott-Aldrich syndrome protein) gene mutations and phenotype. Curr Opin Allergy Clin Immunol. 6:427-436.
  4. Ancliff et al., (2006) Two novel activating mutations in the Wiskott-Aldrich syndrome protein result in congenital neutropenia. Blood. 108(7): 2182-2189.