Common variable immunodeficiency
(CVID) is a group of disorders in which the immune system cannot make antibodies in response to foreign substances that cause infection. The main feature that separates CVID from other immunodeficiencies is low levels of two specific antibodies, immunoglobulin A (IgA) and immunoglobulin G (IgG). People with CVID get more frequent infections, particularly in the sinuses, lungs, and digestive tract. Symptoms most commonly begin in early adulthood, but have been found in children as young as age two. While in most cases the cause of CVID is unknown, the condition has been associated with mutations in at least 10 genes. About 10% of affected people have mutations in the TNFRSF13B gene. The main treatment for CVID is Ig replacement therapy, which stops the cycle of recurrent infections. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.