Genetic STAT5B immunodysregulatory disorder. Genetic STAT5B immunodysregulatory disorder

We describe one patient with a heterozygous missense mutation in the coiled-coil domain of STAT5B. This patient presented with leukocytosis, lymphadenopathy, splenomegaly, necrotizing granulomas, hyper-IgM and autoimmune thrombocytopenia. Mutant STAT5B protein was shown to dominantly-interfere with IL2-induced transcriptional activity resulting in global downregulation of STAT5-regulated genes in patient T cells. The patient exhibited an increase in CD4+ T effector memory cells in the peripheral blood and these cells were resistant to restimulation-induced cell death in vitro.