The CRISPR/Cas-based gene therapy strategy has been applied to the modeling and correction of many forms of IEIs, including SCID, immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX), X-linked MAGT1 deficiency with increased susceptibility to EBV-infection and N-linked glycosylation defect (XMEN), X-CGD, and WAS. The gene discussed is MAGT1; the disease is X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia.