<unk>  <unk>  is an immune disorder characterized by recurrent infections and low antibody levels, specifically in immunoglobulin (Ig) types IgG, IgM and IgA. Generally symptoms include high susceptibility to foreign invaders, chronic lung disease, and inflammation and infection of the gastrointestinal tract. It affects males and females equally. The condition can be found in children or teens but is generally not diagnosed or recognized until adulthood. The average age of diagnosis is between 20-50. However, symptoms vary greatly between people.<unk> " refers to the heterogeneous clinical manifestations of this disorder, which include recurrent bacterial infections, increased risk for autoimmune disease and lymphoma, as well as gastrointestinal disease.<unk>  is a lifelong disease. The cause of<unk>  is poorly understood. Deletions in genes that encode cell surface proteins and cytokine receptors, such as CD19, CD20, CD21, and CD80, is a likely cause. A deletion is a mutation in which part of the chromosome is lost during DNA replication which may include several genes, or as few as a single base pair. Additionally, the disease is defined by T cell defects, namely reduced proliferative capacity. The disease is hard to diagnose, taking on average 6–7 years after onset.<unk>  is a primary immunodeficiency. Treatment options are limited, and usually include lifelong immunoglobulin replacement therapy. This therapy is thought to help reduce bacterial infections. This treatment alone is not wholly effective, and many people still experience other symptoms like lung disease and noninfectious inflammatory symptoms.<unk>  was first diagnosed over 60 years ago, and since has emerged as the predominant class of primary antibody deficiencies.<unk>  is formally diagnosed by levels of IgG and IgA more than two standard deviations below the norm, and no other cause for hypogammaglobulinemia, an abnormally low level of immunoglobulins in the blood. It is thought to affect between 1 in 25,000 to 1 in 50,000 people worldwide.
Common variable immunodeficiency
Severe combined immunodeficiency
X-linked severe combined immunodeficiency
X-linked agammaglobulinemia
Chronic granulomatous disease
Primary immunodeficiency
Wiskott–Aldrich syndrome
Combined immunodeficiencies