X-linked agammaglobulinemia

X-linked agammaglobulinemia is an inherited immunodeficiency, usually caused by BTK mutations, that arrests B-cell development and leaves antibody levels very low.

Bruton tyrosine kinase: A signaling enzyme encoded by BTK that helps immature B cells survive and mature. Mutations in this enzyme cause most cases by disrupting signals required for B-cell development.
Immunoglobulin replacement therapy: Treatment that supplies pooled antibodies, usually by intravenous or subcutaneous infusion. It provides the antibodies patients cannot make and reduces serious infections.
Ogden Bruton: An American pediatrician who described the first recognized case of congenital agammaglobulinemia in 1952. His report of a boy with recurrent infections and absent gamma globulin established the clinical syndrome.
Common variable immunodeficiency: A heterogeneous primary immunodeficiency marked by low immunoglobulin levels and impaired antibody responses. Unlike this disorder, it usually involves B cells that are present but fail to function or mature normally.
B-cell development: The sequence of stages through which bone-marrow precursors become mature antibody-producing B lymphocytes. The disease arrests this process before mature B cells enter circulation.
Flow cytometry: A laboratory method that identifies and counts cells using fluorescently labeled markers. It demonstrates the markedly reduced or absent circulating B-cell population.
Bruton's agammaglobulinemia: The historical name for X-linked agammaglobulinemia, based on Ogden Bruton's original description. The eponym preserves the early clinical account that led to identifying this inherited disorder.
Hyper-IgM syndrome: A group of immunodeficiencies in which antibody class switching is impaired, often leaving IgM normal or high. Its B cells generally develop, but cannot efficiently switch antibody classes.
Pre-B-cell receptor: A temporary receptor on developing B cells that tests whether a rearranged immunoglobulin heavy chain can function. BTK relays signals from this receptor at the developmental checkpoint affected by the disease.
Serum immunoglobulin test: A blood test that measures concentrations of immunoglobulin classes such as IgG, IgA, and IgM. Very low antibody concentrations support the diagnosis and help monitor immune status.

Linked from 2 pages