MAGT1 and X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia: <b>Background:</b> X-linked immunodeficiency with magnesium defect, Epstein-Barr virus (EBV) infection, and neoplasia (XMEN) disease is a rare inborn error of immunity caused by loss-of-function mutations in <i>MAGT1</i>, leading to impaired N-linked glycosylation.