X-linked (Bruton) Agammaglobulinemia

X-linked (Bruton) Agammaglobulinemia is a rare genetic disorder that affects the body's immune system, specifically the ability to produce antibodies. It mainly impacts the B cells, which are responsible for making antibodies that fight infections. People with this condition have very low levels of antibodies, making them more vulnerable to frequent and severe bacterial infections. These infections often affect the ears, lungs, and sinuses. The disorder usually becomes apparent in early childhood when infections start to occur repeatedly. It is caused by a mutation in a gene important for B cell development. Managing this condition involves addressing the increased risk of infections due to the weakened immune defense.

X-linked (Bruton) Agammaglobulinemia is a primary immunodeficiency characterized by a profound deficiency of mature B cells and all classes of immunoglobulins due to mutations in the BTK gene, which encodes Bruton tyrosine kinase. This enzyme is essential for B cell maturation in the bone marrow. The absence of functional B cells leads to markedly reduced serum IgG, IgA, and IgM levels, resulting in impaired humoral immunity. Clinically, affected males present with recurrent bacterial infections, especially from encapsulated organisms such as Streptococcus pneumoniae and Haemophilus influenzae. The condition is inherited in an X-linked recessive pattern, predominantly affecting males. Early diagnosis is critical to prevent complications from infections and to initiate appropriate immunoglobulin replacement therapy.