Immunodeficiency 31a, also known as mendelian susceptibility to mycobacterial diseases due to partial stat1 deficiency, is related to autoimmune lymphoproliferative syndrome and aicardi-goutieres syndrome. An important gene associated with Immunodeficiency 31a is STAT1 (Signal Transducer And Activator Of Transcription 1). Affiliated tissues include lung, and related phenotypes are recurrent viral infections and bcgitis