Disseminated Mycobacterium Avium Infection in a Child with Complete Interferon-γ Receptor 1 Deficiency due to Compound Heterozygosis of IFNGR1 for a Subpolymorphic Copy Number Variation and a Novel Splice-Site Variant

Complete interferon-γ receptor 1 deficiency is a monogenic primary immunodeficiency caused by IFNGR1 germline defects, with autosomal dominant or recessive inheritance, which results in invasive mycobacterial diseases with varying degrees of severity. Most of the autosomal recessive IFNGR1 mutations are homozygous loss-of-function single-nucleotide variants, whereas large genomic deletions and compound heterozygosity have been very rarely reported. Herein we describe the clinical presentation, diagnosis, and successful treatment with hematopoietic stem cell transplantation of a child with disseminated Mycobacterium avium infection due to compound heterozygosity for a subpolymorphic copy number variation and a novel splice-site variant.