The thymidylate synthase enhancer region (TSER) polymorphism increases the risk of thymic lymphoid hyperplasia in patients with Myasthenia Gravis

Myasthenia Gravis (MG) is caused, in approximately 80% of the patients, by autoantibodies against the nicotinic acetylcholine receptor (AChR). The disease is often associated with pathological changes of the thymus: thymic epithelial tumours are present in about 10–20% of the patients, while up to 80% of the patients with early disease onset have thymic hyperplasia. Folate metabolism is required for the production of DNA precursors and for proper DNA methylation reactions, and impaired folate metabolism has been often associated with cellular growth and cancer.