A Unique Pathogenic Heterozygous Hypoxia Up-Regulated Protein 1 (HYOU1) Mutation Presenting With Recurrent Osteomyelitis, Subglottic Stenosis, and Hypoglycemia

The hypoxia up-regulated protein 1 (HYOU1) gene encodes a chaperone protein involved in maintaining cellular homeostasis by reducing oxidative stress and supporting the unfolded protein response in the endoplasmic reticulum and mitochondria. While homozygous HYOU1 mutations have been previously reported in patients with profound immunodeficiency, pancytopenia, and hypoglycemia, the clinical implications of heterozygous mutations remain less defined. We describe a patient with a heterozygous pathogenic HYOU1 mutation who presents with a longstanding history of recurrent infections, medically treated hypoglycemia, and subglottic stenosis due to repeated intubation and inflammation.