Effects of two different variants in the MAGT1 gene on B cell subsets, platelet function, and cell glycome composition

X-linked immunodeficiency with magnesium defect, Epstein-Barr virus (EBV) infection and neoplasia (XMEN) disease is caused by hemizygous loss of function (LOF) gene variants in MAGT1. MAGT1 is a plasma membrane transporter of magnesium (Mg²⁺) that plays a relevant role in immune responses and acts as a second messenger in intracellular signaling, but also it is involved in the glycosylation of proteins. Here we report two gene variants in the MAGT1 gene from two different families with XMEN disease.