What is it about?
This report describes the clinical and laboratory findings in a pair of identical twins discordant for multiple sclerosis. Although the laboratory findings including evidence of prior exposures to the Epstein-Barr Virus were remarkably similar in these two twins, only one of them had a positive history of exposure to mercury containing dental amalgams. The exposed twin also had evidence of demyelination seen on his brain MRI and an elevated serum concentration of the biomarker neurofilament light chain consistent with a diagnosis of multiple sclerosis which were not seen in the unexposed twin.
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Why is it important?
In 2020 the FDA issued an advisory against the use of mercury amalgam fillings in certain high risk groups including people who have multiple sclerosis. A study of monozygotic twins revealed that non-heritable immune system dysregulation possibly triggered by an environmental factor sets the stage for disease initiation and progression in MS (Ingelfinger et al., 2022). This case report calls attention to the additional potential risks associated with the use of mercury amalgam fillings in an asymptomatic identical twin who shares genetics with their symptomatic sibling that was not mentioned in the FDA advisory.
Perspectives
This important case report involved work by many other leading scientists in addition to the authors. We are particularly grateful to Dr. Ronald Booth who performed the analysis for serum neurofilament light chain.
Dr. Marcia H. Ratner
Boston University Chobanian & Avedisian School of Medicine
Read the Original
This page is a summary of: Neurofilament Light Chain and Mercury Amalgam Fillings in Monozygotic Twins Discordant for Multiple Sclerosis Case Report, Neuroimmunology Reports, September 2022, Elsevier,
DOI: 10.1016/j.nerep.2022.100140.
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Resources
FDA Issues Recommendations for Certain High-Risk Groups Regarding Mercury-Containing Dental Amalgam
These groups that may be at a greater risk for potential harmful health effects include: Pregnant women and their developing fetuses; Women who are planning to become pregnant; Nursing women and their newborns and infants; Children, especially those younger than six years of age; People with pre-existing neurological disease such as multiple sclerosis, Alzheimer’s disease or Parkinson’s disease People with impaired kidney function; and People with known heightened sensitivity (allergy) to mercury or other components of dental amalgam
Bates MN, Fawcett J, Garrett N, Cutress T, Kjellstrom T. Health effects of dental amalgam exposure: a retrospective cohort study. Int J Epidemiol. 2004 Aug;33(4):894-902.
Of conditions allegedly associated with amalgam, multiple sclerosis had an adjusted hazard ratio (HR) of 1.24 (95% CI: 0.99, 1.53, P = 0.06).
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