XMEN DISEASE: MAGT1 MUTATION IN A CHILD WITH HYPOGAMMAGLOBULINEMIA

Abstract

<h3>Introduction</h3> X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia (XMEN) disease is a rare disorder caused by mutations in the MAGT1 gene, which codes for a magnesium transporter important in CD8+ T cells and their response. These cells are not activated efficiently in the setting of EBV infection, increasing the likelihood of developing lymphoma. <h3>Case Description</h3> A 9-month-old was evaluated at the hospital due to upper respiratory symptoms. Patient was born at 39 weeks and spent 16 days in NICU due to thrombocytopenia. Physical exam was remarkable for low weight. Laboratories revealed anemia, thrombocytopenia, and hypogammaglobulinemia. Lymphocyte subset panel was normal. Genetic testing showed a pathogenic hemizygous mutation in MAGT1, associated with XMEN disease. Patient was started on intravenous immunoglobulin replacement which he tolerated well. Since then, no other infections have been reported. At 3 years old, patient developed transaminitis. Abdominal ultrasound, hepatitis serology and inflammatory markers were normal. He is being evaluated by Gastroenterology. <h3>Discussion</h3> Regardless of EBV serological status, the cellular and clinical phenotype of XMEN patients is similar, implying that the virus is not responsible for the pathogenesis. Management is based on the individual clinical manifestations. Some patients may require immunoglobulin replacement or prophylactic antibiotic therapy. Recommendations include routine EBV serologies and viral load assessment and malignancy surveillance. A small, controlled trial evaluating the role of magnesium supplementation found no benefit in these patients. Given its rarity and broad spectrum of clinical presentations, there is need to increase awareness of this disease and further investigate possible therapies for these patients.