Partial T cell defects and expanded CD56bright NK cells in an SCID patient carrying hypomorphic mutation in the IL2RG gene
X-linked severe combined immunodeficiency (X-SCID) caused by full mutation of the IL2RG gene leads to T− B+ NK− phenotype and is usually associated with severe opportunistic infections, diarrhea, and failure to thrive. When IL2RG hypomorphic mutation occurs, diagnosis could be delayed and challenging since only moderate reduction of T and NK cells may be present. Here, we explored phenotypic insights and the impact of the p.R222C hypomorphic mutation (IL2RGR222C) in distinct cell subsets in an 8-month-old patient with atypical X-SCID.