This word is not acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. A congenital or acquired deficiency of gamma globulins in the blood.

n. A condition in which gammaglobulins such as immunoglobulins are absent from the blood, or present only in low concentrations

n. a rare immunological disorder characterized by the virtual absence of gamma globulin in the blood and consequent susceptibility to infection

"Too little Btk causes a disease called Bruton's agammaglobulinemia, in which the B-lymphocytes fail to mature and produce antibodies, leading to infections."

immunodeficiency   

agammaglobulinemic