MAGT1 deficiency in XMEN disease is associated with severe platelet dysfunction and impaired platelet glycoprotein N-glycosylation

X-Linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia (XMEN) disease is a primary immunodeficiency due to loss-of-function mutations in the gene encoding for the magnesium transporter 1 (MAGT1). Furthermore, as MAGT1 is involved in the N-glycosylation process, XMEN disease is classified as a Congenital Disorder of Glycosylation. Although XMEN-associated immunodeficiency is well described, the mechanisms underlying platelet dysfunction and responsible for life-threatening bleeding events have never been investigated. […] Our results highlight prominent platelet dysfunction related to MAGT1 deficiency and a defective N-glycosylation in several platelet proteins, that could explain the hemorrhages reported in XMEN patients.