PLCG1 and X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia: Lymphocytes from XMEN patients have decreased calcium flux and phospholipase C-gamma 1 (PLCγ1) activation, and impaired re-stimulation induced cell death upon TCR crosslinking, likely due to impaired signaling through the hypoglycosylated TCR and CD28[1, 4].