Omenn Syndrome in Two Infants with Different Hypomorphic Variants in Janus Kinase 3.

Biallelic null or hypomorphic variants in JAK3 cause SCID and less frequently Omenn syndrome. We investigated homozygous hypomorphic JAK3 mutations in two patients, and expression and function of a novel JAK3 variant in Omenn syndrome. Immunophenotyping of PBMC from the patient with the novel JAK3 variant was undertaken, by flow cytometry and Phosflow after stimulation with IL-2, IL-7, and IL-15.