Neurofilament light chain and mercury amalgam fillings in monozygotic twins discordant for multiple sclerosis case report

The Food and Drug Administration (FDA) has determined that certain groups including people with Multiple Sclerosis (MS) are at greater risk for potential harmful effects of mercury (Hg) vapor released from dental amalgams. This case report explores the potential harmful effects of Hg vapor released from dental amalgams in monozygotic twin brothers discordant MS. The patient and his twin brother both underwent testing for Epstein-Barr virus (EBV) to rule this out as an environmental trigger, neuroimaging and neurofilament light chain (NfL) to confirm the diagnosis of MS, and genetic testing to confirm monozygosity. Only the twin with Hg amalgam fillings developed MS. Both twins tested positive for EBV. Axial T2-FLAIR magnetic resonance images of the twin exposed to Hg revealed multiple periventricular white matter lesions. The twin diagnosed with MS was also found to have elevated serum NfL. Based on the findings presented in this case report and, the latest FDA advisory about the risk of potential harmful effects of Hg vapor released from dental amalgams we recommend extending the advisory against the use of Hg amalgam fillings in persons with MS to include asymptomatic monozygotic twins of a patients diagnosed with MS.