IFNGR1 and bacterial arthritis: Nontuberculous mycobacteriosis caused by Mycobacterium intracellulare is often clinically relevant.[6–10] A recent case reported that a diffuse NTM disease caused by Mycobacterium intracellulare occurred in a child with IFNGR1 deficiency, with a good prognosis after antimycobacterial treatment.[11] A patient diagnosed with septic arthritis was due to NTM infection as Mycobacterium intracellulare was isolated by culture and showed an excellent prognosis with antimycobacterial treatment.[12]