What is common variable immunodeficiency (CVID)?

CVID is a genetic disorder that affects the immune system. People with this condition have low levels of antibodies (proteins that fight infections) in their blood. When the body does not have enough of these antibodies, people may experience frequent infections.

In people with CVID, infections often develop in the respiratory system, ears and sinuses. CVID can increase your risk of developing digestive problems and cancer.

CVID is a primary immunodeficiency disease (PIDD). These diseases are genetic disorders in which a person’s immune system does not work properly.

Who is affected by common variable immunodeficiency (CVID)?

CVID occurs in about 1 out of 25,000 people. It affects males and females in equal numbers. The condition can appear in children or teens, but usually isn’t recognized until adulthood. In most cases, a doctor diagnoses the disorder when a person is between the ages of 20 to 50.

What causes common variable immunodeficiency (CVID)?

A genetic mutation (change) causes CVID. In most cases, this genetic mutation — and CVID symptoms — develop without any apparent cause. In about 10 percent of cases, CVID is hereditary (passed down among family members).

CVID results from defects in the genes involved with the immune system. These defects cause the body to produce abnormally low amounts of a proteins called immunoglobulins, including immunoglobulin G (IgG). Low levels of IgG in the blood can make it difficult for the body to fight infections.

What are the symptoms of common variable immunodeficiency (CVID)?

Symptoms of CVID vary widely from person to person. They can range from mild to severe. Signs and symptoms of CVID include:

  • Breathing problems
  • Chronic cough
  • Diarrhea that causes weight loss
  • Ear infections
  • Frequent sinus infections
  • Recurring lung infections, including pneumonia

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