First Report on Chronic Granulomatous Disease from Nepal and a Review of CYBC1 Deficiency.

ABSTRACT

Chronic granulomatous disease (CGD) primarily results from inherited defects in components of the nicotinamide adenine dinucleotide phosphate oxidase enzyme complex. These include gene defects in cytochrome B-245/558 subunit α/ß and neutrophil cytosolic factors 1, 2, and 4. Recently, homozygous loss-of-function variants in cytochrome B-245 chaperone 1 gene (CYBC1) have been discovered to cause CGD (CYBC1-CGD). Data on variant-proven CGD from low-income countries, the most underprivileged regions of the world, remain sparse due to numerous constraints. Herein, we report the first cohort of patients with CGD from Nepal, a low-income country in the Himalayas' challenging terrain. Our report includes a description of a new case of CYBC1 deficiency who was first diagnosed with CGD at our center. Only a dozen cases of CYBC1-CGD have been described in the literature thus far which have been reviewed comprehensively herein. Most of these patients have had significant infections and autoimmune/inflammatory manifestations. Pulmonary and invasive/disseminated bacterial/fungal infections were the most common followed by skin and soft-tissue infections. Inflammatory bowel disease (IBD) was the most common inflammatory manifestation (median age at diagnosis 9 years) followed by episodes of recurrent/prolonged fever. Other autoimmune/inflammatory manifestations reported in CYBC1-CGD include acute pancreatitis, hemophagocytic lymphohistiocytosis, systemic granulomatosis, interstitial lung disease, arthritis, autoimmune hemolytic anemia, uveitis, nephritis, and eczema. Our analysis shows that patients with CYBC1-CGD are at a significantly higher risk of IBD-like illness as compared to other forms of CGD which merits further confirmatory studies in the future.