US Health Professionals

Evans Syndrome

Is it Evans syndrome or could it be APDS?

Activated PI3K delta syndrome (APDS) and Evans syndrome are both rare chronic conditions. Evans syndrome is an autoimmune condition that causes a lower than normal level of blood cells known as cytopenia. People with Evans syndrome can have two forms of cytopenia at the same time, or they may occur sequentially. APDS is a rare primary immunodeficiency (PI) that causes immune deficiency and immune dysregulation. Immune dysregulation can cause autoimmune complications. In around 30% of cases, people with APDS have autoimmune conditions, with cytopenia being the most common manifestation.

APDS is complex and difficult to diagnose

APDS has a wide variety of symptoms which can make it difficult to recognize. It has been reported that the median delay to diagnosis of APDS is seven years. Sometimes people can be diagnosed with other conditions, like Evans syndrome, until APDS is confirmed through a genetic test.

In a study of children (n=80) with Evans syndrome who underwent genetic testing, 40% had abnormalities in certain genes that are known to cause PI, including PIK3CD, which causes APDS.

How do Evans syndrome & APDS affect the body?

  • In Evans syndrome the body’s immune system produces antibodies that mistakenly destroy the blood cells, platelets and sometimes certain white blood cells known as neutrophils, resulting in cytopenia.
  • The two common forms of cytopenia in Evans syndrome are autoimmune hemolytic anemia (AIHA) and immune thrombocytopenic purpura (ITP).
  • In Evans syndrome the body’s immune system produces antibodies that mistakenly destroy the blood cells, platelets and sometimes certain white blood cells known as neutrophils, resulting in cytopenia.
    • In people with APDS, the process of making white blood cells is disrupted; this can result in too many underdeveloped white bloodcells and not enough functioning white blood cells in the body. When the white cells are not functioning as they should, this is called immune dysregulation and can cause autoimmune conditions.
    • The most common autoimmune manifestation in APDS is cytopenia.

If you have experienced a lack of response to standard Evans syndrome treatments, or have cytopenia plus some of the symptoms outlined below, discuss with your doctor to see if you are a candidate for genetic testing for APDS.

Most Common APDS Signs & Symptoms

The most common, and often earliest reported APDS symptoms include frequent and severe infections of the ears, sinuses, and upper and lower respiratory tracts which begin in infancy.

Common APDS signs & symptoms include:

Ear, Sinus, and Respiratory Tract Infections

96-100% of reported cases

Enlarged Tonsils, Lymph Nodes, or Spleen

71-89% of reported cases

Chronic Cough

51% of reported cases

Gastrointestinal (Digestive Tract) Issues

51% of reported cases

Herpes Infections

36-49% of reported cases

Autoimmune and Autoinflammatory Disorders

~30% of reported cases

Low Numbers of Blood Cells

~30% of reported cases

Developmental Delay

10-31% of reported cases


12-25% of reported cases

People who suffer from any two or more of the above conditions, should consider APDS.
Lymphoma under the age of 26 should raise suspicion of APDS.

A Genetic Test May Shorten The Diagnostic Journey.

  • Before patients are correctly diagnosed with APDS, they often have a lengthy wait for a diagnosis involving multiple visits to various specialists. Symptoms are treated without identifying the underlying cause.
  • The goal of a quick diagnosis and treatment is to interrupt disease progression to permanent damage or malignancy.
  • As primary immunodeficiencies are inherited, family members of a confirmed patient should be genetically tested. While family members may not have the same symptoms or any symptoms, they may still carry the genetic condition and pass it onto their biological children.
  • If you have been going to multiple doctors and not getting answers to your
    condition, consider genetic testing. Talk with your doctor about getting a no-charge genetic test from the navigateAPDS program*.

Every year new genetic variants are picked up by the latest genetic tests.

Five years ago we had only identified 200 genes associated with PI, and by 2019 we had identified 407.

If you have had a genetic test for a PI such as APDS in the past, speak to your doctor to see if retesting is appropriate for you.

Download this information sheet about our no-charge genetic testing program to share with your doctor.

*This program is currently available in the US and Canada only. Eligibility requirements apply.

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