Agammaglobulinemia

Alternative names:

Bruton agammaglobulinemia; X-linked agammaglobulinemia

Definition:

An inherited disorder characterized by very low levels of protective immunoglobulins; affected people develop repeated infections.

Causes, incidence, and risk factors:

Agammaglobulinemia is inherited as an X-linked recessive trait in which an inborn error blocks B-cell differentiation. It causes the body to produce very little (if any) gamma globulin (IgG) and other immunoglobulins in the bloodstream. Immunoglobulins are molecules that play a significant role in the immune response, which protects against illness and infection.

In the absence of protective immunoglobulins, affected individuals develop repeated infections. People with this disorder are particularly susceptible to Hemophilus influenza, pneumococcus infections, staphylococcus infections and repeated viral infections. The upper respiratory tract, lungs, and skin are common sites of infection. The incidence is approximately 1 out of 100,000 people.