Although in our patient we observed only flat warts (which were presumed to be due to HPV) without life-threatening viral infections, the description of additional patients may broaden the phenotype of JAK1 deficiency in humans and provide opportunities to further assess the relative importance of JAK1 for viral protection in hematopoietic and non-hematopoietic cell types. The gene discussed is JAK1; the disease is viral infectious disease.