Definition of Agammaglobulinemia:

Agammaglobulinemia is an inherited disorder in which there are very low levels of protective immune system proteins called immunoglobulins. People with this disorder repeatedly develop infections.

Causes, incidence, and risk factors:

Agammaglobulinemia is a rare disorder that mainly affects males. It is the result of a genetic abnormality that blocks the development of normal, mature immune system cells called B lymphocytes.

As a result, the body produces very little (if any) immunoglobulins in the bloodstream. Immunoglobulins play a major role in the immune response, which protects against illness and infection.

Without protective immunoglobulins, people with agammaglobulinemia repeatedly develop infections. People with this disorder are particularly susceptible to bacterial infections caused by Haemophilus influenzae, pneumococci (Streptococcus pneumoniae), and staphylococci, as well as to repeated viral infections. Common sites of infection include:

• Gastrointestinal tract
• Lungs
• Skin
• Upper respiratory tract

People with this condition may have a family history of agammaglobulinemia (or another immune disorder).