X-linked agammaglobulinemia (XLA) is a clinically variable form of isolated agammaglobulinemia, an inherited immunodeficiency disorder, and is characterized in affected males by recurrent bacterial infections during infancy. The disease is MONDO_0010421 (Bruton-type agammaglobulinemia). Also known as: BTK deficiency, BTK-deficiency, Bruton agammaglobulinemia tyrosine kinase deficiency, Bruton type agammaglobulinemia, Bruton's Sex-linked agammaglobulinemia, Bruton's X-linked agammaglobulinemia, Bruton's agammaglobulinaemia, Bruton's type agammaglobulinemia.