label: X-Linked Agammaglobulinemia
label_lc: x-linked agammaglobulinemia
description: An X-linked recessive inherited immunodeficiency disorder caused by mutation of the BTK gene, which is located on the X chromosome. It almost always affects males. Individuals with this disorder have low numbers of B-cells and extremely low levels of all types of immunoglobulins. This results in susceptibility to recurrent infections, leading to organ damage.