Wiskott-Aldrich Syndrome (WAS)
Definition of WAS
Wiskott-Aldrich syndrome is a PI disease that affects both the T and B lymphocytes. In addition, the platelets—blood cells that help control bleeding—are reduced in number and size. People with WAS experience frequent bacterial,
viral, and fungal infections; eczema of the skin; and an increased tendency to bleed.
WAS is caused by mutations—or mistakes—in the gene that produces a protein named for the disorder, the Wiskott-Aldrich Syndrome Protein (WASP), which is located on the X chromosome. Because the gene defect is carried on
the X chromosome (X-linked recessive), only boys can inherit WAS.
People with WAS demonstrate a classic pattern of symptoms:
- Increased tendency to bleed, caused by a significantly reduced number of platelets
- Recurring bacterial, viral, and fungal infections
- Eczema of the skin
Symptoms of WAS
Individuals with WAS can develop different symptoms. Some people have all three classic symptoms; including: low platelets, immunodeficiency, and eczema while others experience only low platelet counts and bleeding. All are related
to the mutation of the WAS gene.
- Bleeding: A reduction in the size and number of platelets is a hallmark of WAS. These small platelets are unique to WAS, and their presence is useful in making a diagnosis. Bleeding into the skin may cause bluish-red spots
(called petechiae) ranging in size from small pinheads to large bruises. Boys with WAS may also experience bloody bowel movements (especially in infancy), bleeding gums, and prolonged nose bleeds. Bleeding into the brain is
a particularly dangerous complication.
- Infections: Ear infections, sinus infections and pneumonia are common in WAS due to the deficiency of both B and T lymphocyte function. More severe infections of the bloodstream may also occur, as well as meningitis or severe
- Eczema: People with classic WAS frequently suffer from eczema. In infants, the eczema may resemble “cradle cap” or severe diaper rash; in older boys, it may be limited to the skin creases around the front of the
elbow, around the wrist and neck, and behind the knee.
- Autoimmune manifestations: A high incidence of “autoimmune-like” (conditions that result from the unhealthy immune system attacking the patient's own body) symptoms are common in both infants and adults with WAS.
The most common of these are vasculitis, an inflammation of the blood vessels; hemolytic anemia, where the body destroys its own blood cells; and idiopathic thrombocytopenia purpura (ITP), where the immune system attacks the
- Malignancies: Cancer can occur more frequently in patients with WAS. Most of these cancers, such as lymphoma or leukemia, involve the B cells.
Diagnosis of WAS
Because the platelet abnormalities of WAS are almost always present even in the cord blood at birth, the simplest way to diagnose WAS is to obtain a platelet count and determine the platelet size. WAS platelets are significantly smaller
than normal platelets. In children over the age of 2, the frequency of infections and deficiencies in the immune system can be used to support the diagnosis.
The diagnosis is confirmed by demonstrating an absence of the WAS protein in blood cells, or by the identification of a mutation within the WAS gene.
Only your doctor can determine which treatment is right for you and your specific health needs. Visit our Treating PI section to read about the types of PI treatment and download questions to ask your doctor.