['Infection with the Epstein-Barr virus (EBV) is associated with an increased risk of multiple sclerosis (MS).', 'We sought genetic loci influencing EBV nuclear antigen-1 (EBNA-1) IgG titers and hypothesized that they may play a role in MS risk.', 'We performed a genome-wide association study (GWAS) of anti-EBNA-1 IgG titers in 3599 individuals from an unselected twin family cohort, followed by a meta-analysis with data from an independent EBNA-1 GWAS. We then examined the shared polygenic risk between the EBNA-1 GWAS (effective sample size (N', 'We identified one locus of strong association within the human leukocyte antigen (HLA) region, of which the most significantly associated genotyped single nucleotide polymorphism (SNP) was rs2516049 (p\u2009=\u20094.11\u2009×\u200910'] Are genetic loci for Epstein-Barr virus nuclear antigen-1 associated with risk of multiple sclerosis?