X-linked agammaglobulinemia is is an X-linked recessive inherited disease marked by recurrent Bacterial Infections in the airways and GI tract. It also predisposes affected individuals to Chronic enterovirus infections. It occurs with a prevalence of approximately 1:200,000. The disease is caused by the deficient production of immunoglobulin as a result of mutations in the Gene coding for Bruton's tyrosine kinase (Btk) and is characterized by Impaired maturation of B lymphocytes. Patients are treated with regular venous or subcutaneous injections of immunoglobulin.