What is Agammaglobulinemia

Agammaglobulinemia is a rare primary immunodeficiency disorder characterized by a near-total absence of antibodies (immunoglobulins) in the blood, which leaves individuals highly susceptible to recurrent bacterial infections. It is caused by genetic defects that prevent the maturation of B-cells, the white blood cells responsible for producing protective antibodies.

What causes Agammaglobulinemia?

The underlying mechanism of Agammaglobulinemia involves a failure in the development of B-cells within the bone marrow. In the most common form, X-linked agammaglobulinemia (XLA), a mutation in the BTK gene prevents B-cells from maturing into plasma cells. Without these cells, the body cannot mount an effective immune response against pathogens, leading to frequent infections of the ears, sinuses, lungs, and skin.

Who is typically affected by Agammaglobulinemia?

Agammaglobulinemia is primarily diagnosed in early childhood, often between the ages of 6 and 18 months, as maternal antibodies provided during pregnancy begin to fade. The condition affects males significantly more than females, particularly in X-linked cases. While global prevalence is difficult to pinpoint due to underdiagnosis, it is estimated to affect approximately 1 in 200,000 to 1 in 500,000 live births.

How is Agammaglobulinemia classified?

Clinicians generally divide the condition into two major categories based on genetic inheritance patterns:

• X-linked Agammaglobulinemia (XLA): The most common form, caused by mutations in the BTK gene on the X chromosome.


• Autosomal Recessive Agammaglobulinemia: A rarer form caused by mutations in various genes (such as mu-heavy chain or BLNK) that can affect both males and females equally.

How does this differ from other immune disorders?

Unlike common variable immunodeficiency (CVID), which often presents later in life and may involve some antibody production, Agammaglobulinemia is defined by a severe, systemic lack of mature B-cells and antibodies from infancy. At DiseaseMaps.org, 4 community members living with Agammaglobulinemia have connected to share their unique experiences with managing this lifelong condition.

Next steps

• Consult an immunologist to discuss regular immunoglobulin replacement therapy (IRT).


• Maintain a detailed log of all infections to share with your medical team.


• Join the DiseaseMaps community to connect with other families navigating Agammaglobulinemia.


• Ask your genetic counselor about family screening if you have a suspected diagnosis of Agammaglobulinemia.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Agammaglobulinemia


• Orphanet: X-linked agammaglobulinemia


• OMIM (Online Mendelian Inheritance in Man): Agammaglobulinemia entry


• Immune Deficiency Foundation (IDF): Understanding Primary Immunodeficiencies