Table 2.
Summary of genetic studies in humans
| Population | Measured | Significant findings | Reference |
|---|---|---|---|
| Subset of the Avon Longitudinal Study of Parents and Children (Bristol, UK) | Hg content from freeze-dried umbilical cord tissue; sociodemographic cofactors, nutrition, genetic polymorphisms; Wechsler Intelligence Scale for children IQ at age 8 years | MeHg×total IQ interactions detected for paraoxonase 1 (rs662), progesterone receptor (rs1042838), and brain-derived neurotrophic factor (rs2049046); transferrin (rs3811647) were associated with Hg concentrations | Julvez et al., 2013 [27] |
| Dental professionals | Polymorphisms in key GSH-synthesizing enzymes | Five polymorphisms were significantly associated with urine Hg levels (GSTT1 deletion), hair Hg levels (GSTP1-105, GSTP1-114, GSS 5′), or both (SEPP1 3′UTR) | Goodrich et al., 2011 [28] |
| General and autistic populations | Genetic sequences of four genes, L-type amino acid transporter 1 (LAT1), divalent metal transporter 1 (DMT1), metal-regulatory transcription factor 1 (MTF1), and metallothionein 1a (MT1a) | Analysis failed to show association with autism for any variant evaluated, suggesting that variations in the ability of these genes to process and transport Hg may not play a significant role in the etiology of autism | Owens et al., 2011 [29] |
| Volunteers exposed to MeHg following fish consumption | Role of eNOS gene polymorphisms (T-786C and Glu298Asp) on nitrite concentrations following Hg exposure | • T-786C and Glu298Asp were not associated with an increased risk for cardiovascular diseases in MeHg-exposed subjects • Age, gender, and the presence of intron 4 polymorphism contributed to nitrite reduction as a result of blood Hg concentration • The 27 nt repeat polymorphism of intron 4 in the eNOS gene increases susceptibility to cardiovascular diseases after MeHg exposure by modulating NO levels |
de Marco et al., 2012 [31] |
| Individuals from Northern Sweden | Polymorphisms in GSH-synthesizing or GSH-conjugating genes and MeHg and risk of MI | No statistically significant genetic modifying effects were seen for the association between plasma eicosapentaenoic+docosahexaenoic acid or erythrocyte-Hg and risk of MI | Engström et al., 2011 [32] |
eNOS endothelial nitric oxide, GSH glutathione, Hg mercury, IQ intelligence quotient, MeHg methylmercury, MI myocardial infarction, NO nitric oxide