A Birth Cohort Study about the Genetic Modification of Prenatal Methylmercury Association with Child Cognitive Development

Abstract

Genetic predisposition may affect neurodevelopmental outcomes of prenatal methylmercury exposure. We examined suspected heterogeneities for modification of exposure-related neurodevelopment in children from the Avon Longitudinal Study of Parents and Children (ALSPAC, 1991-2000), Bristol, United Kingdom. A subgroup (n = 1127 from a pilot study and 1045 from the present study) was identified based on the availability of the mercury concentration of cord tissue as a measure of prenatal methylmercury exposure, data on 247 single-nucleotide polymorphisms (SNPs), as well as the Wechsler Intelligence Scale for Children Intelligence Quotient (IQ) scores. Log10-transformed mercury concentration was positively associated with IQ, but adjustment confounding cofactors attenuated this association. Enhanced interaction with methylmercury was replicated in the new study for the minor allele of rs1042838 (progesterone receptor) (Beta; 95% Confidence Interval) = (-11.8; -23.0, -0.6) (P-for-interaction = 0.004) and weakly for rs662 (paraoxonase 1) (-3.6; -11.4, 4.3) (P = 0.117). In the joint sample, new interacting single-nucleotide polymorphisms (SNPs) were discovered in relation to superoxide dismutase 2, ATP binding cassette subfamily A member 1, and metallothionein 1M genes. While the low-level prenatal exposure to methylmercury was not associated with child cognition, progesterone receptor rs1042838 minor alleles revealed a negative association of mercury exposure with IQ.

Impact of Nut Consumption on Cognition across the Lifespan

“…Linking the previous findings relating the consequences of increased nut consumption by mothers during pregnancy to the later neuropsychological traits of their children [ 24 ], and further applying public health recommendations to an entire population, for example, recommending pregnant women to consume a daily serving of nuts throughout the prenatal period, might be hypothesized to increase the population mean IQ score by a few points. This is not clinically significant at the individual level; still, the impact on the IQ distribution at the population level might represent a significant reduction in the proportion of children with learning problems or low IQ scores [ 24 , 29 ]. Depending on the findings of future research, this could be a potentially impactful health promoting message for the population, possibly akin to the promotion of long-term breastfeeding and/or the recommendation to stop smoking during pregnancy.…”

Developmental fluoride neurotoxicity: an updated review

“…Recent studies have also identified possible genetic predisposition to fluoride neurotoxicity [113, 147]. This means that some subgroups of the general population will be more vulnerable to fluoride exposure so that exposure limits aimed at protecting the average population may not protect those with susceptible genotypes, as has been shown, e.g., for methylmercury neurotoxicity [148]. The impact of iodine deficiency on fluoride vulnerability also needs to be considered [143].…”

Human Health and Ocean Pollution

“…Mercury exposure later in childhood and also in adolescence can also cause damage because the human brain continues to develop throughout this time [ 70 ]. Genetic factors may increase vulnerability to methylmercury in some individuals [ 71 ].…”