What causes common variable immunodeficiency (CVID)?

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.