Agammaglobulinemia (X-Linked)
X-linked agammaglobulinema is a primary immunodeficiency characterized by very low levels of immunoglobulins (proteins made by the immune system to help fight infections). People affected by this condition generally begin developing frequent and recurrent bacterial infections from about 6 months of age. Commonly diagnosed infections include lung infections (pneumonia and bronchitis), middle ear infections, conjunctivitis, sinus infections, various skin infections, and infections that are associated with chronic diarrhea. X-linked agammaglobulinemia is caused by changes in the BTK gene and is inherited in an X-linked recessive manner.