Genetic Basis of Patients with Bacille Calmette‐Guérin Osteomyelitis in Japan: Identification of Dominant Partial Interferon‐γ Receptor 1 Deficiency as a Predominant Type

Interferon (IFN)-gamma-mediated immunity plays an important role in host defense against intracellular pathogens, especially mycobacteria. Six Japanese children with bacille Calmette-Guérin (BCG) osteomyelitis were evaluated (1 disseminated, 3 multiple, and 2 solitary types) for mutations of genes involved in interleukin-12-dependent, IFN-gamma-mediated immunity. Heterozygous small deletions with frameshift (818del4 and 811del4) that are consistent with the diagnosis of partial dominant IFN-gamma receptor 1 (IFN-gammaR1) deficiency were detected in 3 unrelated patients. Expression of IFN-gammaR1 on monocytes was significantly increased in all 3 patients. Screening of family members with recurrent and disseminated mycobacterial infections found the identical deletion in 1 of the fathers. Antimycobacterial treatment was effective in these patients and resulted in good clinical outcome. This study demonstrated that partial dominant IFN-gammaR1 deficiency was the most common in Japanese patients who showed predisposition to curable BCG osteomyelitis.