Wiskott-Aldrich Syndrome

Overview

Wiskott-Aldrich syndrome is a rare genetic disorder that affects the immune system and the platelets, the blood cells responsible for clotting. It is classically described by a triad of features: recurrent infections from a weakened immune system, a tendency to bruise and bleed because of low and unusually small platelets, and eczema, an itchy inflammatory skin condition. The severity varies widely, from milder forms to severe disease that appears in infancy.

The condition is caused by changes in a gene on the X chromosome, so it almost always affects boys, while girls usually act as carriers. Because the underlying problem is present from birth, signs often appear early in life. Advances in diagnosis and treatment, including stem cell transplantation, have greatly improved the outlook for many children.

Symptoms

The combination of bleeding, infection, and skin problems is the hallmark, though not every child shows all features equally.

• Bleeding and bruising: Easy bruising, tiny red or purple skin spots, nosebleeds, bleeding gums, and blood in the stool, often noticed in infancy because of low and small platelets.
• Frequent infections: Recurrent ear, sinus, lung, and skin infections due to the weakened immune system, sometimes with more serious or unusual infections.
• Eczema: Itchy, red, sometimes weeping skin that can range from mild to severe.
• Other features: An increased risk of autoimmune problems (where the immune system attacks the body) and, over time, certain cancers such as lymphoma.

Causes

Wiskott-Aldrich syndrome is caused by mutations in the WAS gene, which provides instructions for a protein that helps immune cells and platelets work and move properly. When this protein is missing or faulty, both the immune defense and platelet function are impaired.

• Genetic inheritance: The gene is on the X chromosome and inherited in an X-linked recessive pattern, which is why it almost always affects boys.
• Carrier mothers: A mother who carries one altered copy usually has no symptoms but can pass the gene to her children.
• New mutations: In some cases the gene change arises newly, with no prior family history.

The specific mutation influences how severe the disease is, ranging from milder platelet problems to the full syndrome.

Risk Factors

• Being male, since the condition is X-linked
• A family history of Wiskott-Aldrich syndrome or unexplained bleeding and immune problems in male relatives
• A mother known to carry a change in the WAS gene

Because it is inherited, the condition cannot be acquired later in life; risk is determined at birth by the genetic makeup.

Diagnosis

Doctors suspect the syndrome in a boy with the combination of bleeding, infections, and eczema, then confirm it with laboratory tests.

• Blood count and platelet size: Shows a low platelet count with characteristically small platelets, an important clue.
• Immune function tests: Measure antibody levels and immune cell function, which are often abnormal.
• Protein and genetic testing: Tests for the WAS protein and confirmatory genetic analysis of the WAS gene give a definitive diagnosis.
• Family testing and counseling: Used to identify carriers and inform future pregnancies.

Treatment

Treatment aims to control symptoms, prevent and treat infections and bleeding, and, when possible, correct the underlying immune defect.

• Stem cell (bone marrow) transplantation: The main curative treatment, replacing the faulty immune and blood-forming cells with healthy donor cells; outcomes are best when done early with a well-matched donor.
• Infection prevention and treatment: Prophylactic antibiotics, prompt treatment of infections, and immunoglobulin replacement to boost antibody defenses.
• Bleeding management: Platelet transfusions for serious bleeding and careful avoidance of injury; removing the spleen is used cautiously in selected cases.
• Skin care: Moisturizers and topical treatments to manage eczema.
• Monitoring: Ongoing surveillance for autoimmune complications and cancers.
• Gene therapy: An emerging approach being studied for selected patients.

Prevention

The syndrome itself cannot be prevented, but complications can be reduced and families can plan ahead.

• Genetic counseling and carrier testing for families with a known history
• Prompt treatment of infections and use of preventive medicines as advised
• Keeping recommended vaccinations up to date under specialist guidance
• Avoiding situations with high injury or bleeding risk when platelets are low
• Regular specialist follow-up to catch autoimmune or cancer complications early

When to See a Doctor

A child with unexplained easy bruising or bleeding, frequent serious infections, and persistent eczema should be evaluated by a doctor. Seek emergency care immediately for:

• Heavy or uncontrolled bleeding, or signs of bleeding in the brain such as a severe headache, vomiting, or unusual drowsiness
• A high fever or a rapidly worsening infection
• Difficulty breathing
• Sudden severe weakness or confusion

Early specialist referral to an immunology center is important for diagnosis and planning treatment.

Related Topics

Frequently Asked Questions

References

1. National Institute of Allergy and Infectious Diseases (NIAID).
2. MedlinePlus, U.S. National Library of Medicine. Wiskott-Aldrich syndrome.
3. Immune Deficiency Foundation.
4. National Organization for Rare Disorders (NORD).