Early-Onset Merkel Cell Carcinoma is Associated with Germline Defects in DNA Repair Genes and a Rare Immunodeficiency

Abstract

Background and aims: Merkel cell carcinoma (MCC) is a rare neuroendocrine skin cancer associated with immunosuppression and advanced age. Only 10% of patients present with MCC below age 50, and fewer than 0.1% present below age 30. Two patients with early-onset MCC (ages 14 and 22) were identified among patients followed at the NIH for X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia (XMEN) disease, which is caused by mutations in the magnesium transporter 1 (MAGT1) gene.