MAGT1 and neoplasm: X-linked immunodeficiency with magnesium defect, Epstein–Barr virus (EBV) infection and neoplasia (XMEN) is another X-linked immunodeficiency caused by pathogenic variants in MAGT1 (OMIM #300715), encoding a magnesium channel required for the control of EBV infection and neoplasia (Li et al. 2014).