This study provides proof of principle for the application of targeted next-generation sequencing panels in countries with limited diagnostic resources. The effect of genetic diagnosis on clinical care requires continued improvements in therapeutic resources for these patients.

Background Hyper‐IgE syndromes (HIES) are distinct diseases characterized by recurrent cutaneous and lung infections, eczema, and elevated serum IgE level. Methods In this study, clinical manifestations, immunologic findings, and genetic studies of all patients with HIES in the Iranian national registry database were evaluated. Results A total of 129 HIES patients with a median age of 14.0 (9.0‐24.0) years were followed up for a total of 307.8 patient‐years. Genetic studies showed heterozygous STAT3 mutations in 19 patients and homozygous DOCK8 mutation in 16 patients. The mean of National Institutes of Health score in STAT3‐deficient patients was higher than in patients with DOCK8 mutation (P = 0.001). It was shown that the presence of pneumatocele and hematologic complication were significantly frequent in STAT3‐deficient cases compared to patients with DOCK8 deficiency (P = 0.001 and P = 0.002, respectively). Moreover, the median IgE serum levels were higher in patients with STAT3 gene mutation than in patients with DOCK8 gene mutation (P = 0.02). The eosinophils’ count was enhanced in patients with DOCK8 deficiency than in patients with STAT3 gene defects (P = 0.02). Conclusion Specific molecular study of STAT3 and DOCK8 mutations in patients with HIES clinical phenotype could help the physician to definitively characterize the disease. Since HIES showed the highest rate of unsolved combined immunodeficiency, investigation of other genetic and environmental factors could also help in understanding the mechanism of remaining patients as well as providing strategy into therapeutic modalities.