Skip Navigation LinksHome > September 2013 - Volume 24 - Issue 5 > Prenatal Methylmercury Exposure and Genetic Predisposition t...
Epidemiology:
doi: 10.1097/EDE.0b013e31829d5c93
Neurobehavior

Prenatal Methylmercury Exposure and Genetic Predisposition to Cognitive Deficit at Age 8 Years

Julvez, Jordia,b; Smith, George Daveyc; Golding, Jeand; Ring, Susane; St. Pourcain, Beatec; Gonzalez, Juan Ramonb; Grandjean, Philippea,f

Supplemental Author Material
Collapse Box

Abstract

Background: Cognitive consequences at school age associated with prenatal methylmercury (MeHg) exposure may need to take into account nutritional and sociodemographic cofactors as well as relevant genetic polymorphisms.

Methods: A subsample (n = 1,311) of the Avon Longitudinal Study of Parents and Children (Bristol, UK) was selected, and mercury (Hg) concentrations were measured in freeze-dried umbilical cord tissue as a measure of MeHg exposure. A total of 1135 children had available data on 247 single-nucleotide polymorphisms (SNPs) within relevant genes, as well as the Wechsler Intelligence Scale for Children Intelligence Quotient (IQ) scores at age 8 years. Multivariate regression models were used to assess the associations between MeHg exposure and IQ and to determine possible gene–environment interactions.

Results: Hg concentrations indicated low background exposures (mean = 26 ng/g, standard deviation = 13). Log10-transformed Hg was positively associated with IQ, which attenuated after adjustment for nutritional and sociodemographic cofactors. In stratified analyses, a reverse association was found in higher social class families (for performance IQ, P value for interaction = 0.0013) among whom there was a wider range of MeHg exposure. Among 40 SNPs showing nominally significant main effects, MeHg interactions were detected for rs662 (paraoxonase 1) and rs1042838 (progesterone receptor) (P < 0.05) and for rs3811647 (transferrin) and rs2049046 (brain-derived neurotrophic factor) (P < 0.10).

Conclusions: In this population with a low level of MeHg exposure, there were only equivocal associations between MeHg exposure and adverse neuropsychological outcomes. Heterogeneities in several relevant genes suggest possible genetic predisposition to MeHg neurotoxicity in a substantial proportion of the population. Future studies need to address this possibility.

© 2013 by Lippincott Williams & Wilkins, Inc

Twitter  Facebook

Login

Article Tools

Share