X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia (XMEN)
Related gene: MAGT1
Inheritance pattern: X-linked recessive
X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia (XMEN) is seen in boys and is characterized by low CD4 T cells, chronic Epstein-Barr virus (EBV) infections, and lymphoproliferative disorders related to the EBV. Individuals have decreased cytolytic function of natural killer (NK) and CD8 T cells, and may have decreased antibody responses due to their low CD4 T cells. Oral magnesium supplementation has been proposed in the treatment of this condition, but it is not clear whether it is clinically helpful. Hematopoietic stem cell transplantation (HSCT) may be curative, though there is limited experience.