DNA Repair and Detoxifying Gene Polymorphisms in Patients with Multiple Sclerosis and Dental Amalgam Fillings

Abstract

Objective: The present study was designed to evaluate the influence of Metallothionein (MT), detoxifying (GSTs) and repair (OGG1, XRCC1) gene polymorphisms on the risk of Multiple Sclerosis (MS) related to metal exposure.

Materials and Methods: One heavy (Mercury; Hg) and two essential metals (Copper; Cu and Zinc; Zn) from dental amalgam fillings were selected. Our study subjects were divided into 4 groups, namely, MS patients not carrying dental amalgam fillings (n=20); patients carrying dental amalgam fillings (n=20); control subjects not carrying dental amalgam fillings (n=20) and control subjects carrying dental amalgam fillings (n=20). The levels of urinary metals detected with Atomic Absorption Spectrometry (AAS) and gene polymorphisms were analyzed with Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP).

Results: Subjects with polymorphic OGG1 genotype had 3 times higher MS risk and subjects with dental amalgam fillings had significantly more urinary Hg levels compared to subjects without dental amalgam fillings.

Conclusion: Considering the information on urinary metal levels, OGG1 Ser326Cys gene polymorphisms may modify the repairing of oxidative products. However, no significant association between OGG1 gene polymorphism and urinary Hg levels was observed.