Identification of a Novel Mutation in MAGT1 and Progressive Multifocal Leucoencephalopathy in a 58-Year-Old Man with XMEN Disease

Fatima Dhalla, Sarah Murray, Ross Sadler, Benjamin Chaigne-Delalande, Tomohiko Sadaoka, Elizabeth Soilleux, Gulbu Uzel, Joanne Miller, Graham Peter Collins, Christian Simon Ross Hatton, Malini Bhole, Berne Ferry, Helen M. Chapel, Jeffrey I. Cohen, Smita Y. Patel

XMEN disease (X-linked immunodeficiency with Magnesium defect, Epstein-Barr virus infection and Neoplasia) is a novel primary immune deficiency caused by mutations in MAGT1 and characterised by chronic infection with Epstein-Barr virus (EBV), EBV-driven lymphoma, CD4 T-cell lymphopenia, and dysgammaglobulinemia [1]. Functional studies have demonstrated roles for magnesium as a second messenger in T-cell receptor signalling [1], and for NKG2D expression and consequently NK- and CD8 T-cell cytotoxicity [2]. 7 patients have been described in the literature; the oldest died at 45 years and was diagnosed posthumously [1-3]. We present the case of a 58-year-old Caucasian gentleman with a novel mutation in MAGT1 with the aim of adding to the phenotype of this newly described disease by detailing his clinical course over more than 20 years.