Therefore, we have now established a reversible Brg1 KO model, and found that restoring Brg1 expression in the mice can produce therapeutic effects, with Brg1 reexpression in only minor fractions (as low as 8%) of Treg cells sufficient for rescuing the mice with slightly less severe phenotypes, suggesting a simple, robust, and safe approach for treating IPEX and IPEX-like diseases. The gene discussed is SMARCA4; the disease is immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome.