'''Primary immunodeficiency''' is a group of rare inherited disorders of the immune system, including adenosine deaminase deficiency, severe combined immunodeficiency (SCID), and ataxia-telangectasia. | '''Primary immunodeficiency''' is a group of rare inherited disorders of the immune system, including adenosine deaminase deficiency, severe combined immunodeficiency (SCID), and ataxia-telangectasia. |