Polymorphism in autoimmune regulator (AIRE) gene is associated with various autoimmune disorders. Abnormal AIRE expression is associated with the development of myasthenia gravis (MG). We investigated the association of polymorphism in AIRE gene and the clinical features and severity of MG. The frequencies of alleles and genotypes were compared between 480 MG patients and 487 healthy controls, as well as among subgroups of MG patients. The frequencies of rs3761389 G allele in MG group (OR = 1.213, CI 95% 1.014-1.451, p = 0.035) and in mild (Oosterhuis score 0-2) subgroup (OR = 1.393, CI 95% 1.110-1.751, p = 0.004) were significantly higher than those in the control group. There were significant differences in the frequencies of rs3761389 genotypes (OR = 1.20, CI 95% 1.00-1.43, p = 0.046, log-additive model) and mild subgroup (OR =1.32, CI 95% 1.03-1.69, p = 0.0058, log-additive model) compared with the control group. A Logistic regression analysis did not identify rs3761389 genotype as an independent risk factor to predict the severity of MG. This study provides the necessary preliminary data on the association with rs3761389 in AIRE gene with the susceptibility of MG, but not with the severity of MG. (C) 2017 Elsevier Ltd. All rights reserved.