BackgroundMercury is a neurotoxic environmental pollutant. However, the literature on the neurodevelopmental effect of low-level prenatal mercury exposure from maternal fish intake is inconsistent. We assessed the association between prenatal mercury exposure and infant neurodevelopment in coastal areas of 4 Mediterranean countries.MethodsThis was a prospective cohort study that planned to enroll approximately 1700 mother–infant pairs. Pregnant women and their newborn children were recruited in selected hospitals of the study areas. Biological samples, including maternal hair and cord blood, were collected from mothers and children, and the concentrations of mercury and other elements were measured. Exposures to lifestyle, environmental, and social factors were assessed through questionnaires. The main outcome was child neurodevelopment at 18 months, as measured by the Bayley Scales of Infant and Toddler Development, Third Edition.ConclusionsThis cohort has a number of strengths. First, mercury concentration was measured in several biological samples, which allows for a better understanding of mercury kinetics and is useful for sensitivity analyses. Therefore, we expect to be able to adjust for the potential confounding effects of lifestyle and social factors and for the effects of other elements that were measured in the biological samples. Finally, this is a multinational study and thus permits assessment of the relation between mercury and child neurodevelopment in different populations.
Cohen syndrome, caused by mutations in the COH1 gene, is an autosomal recessive disorder consisting of mental retardation, microcephaly, growth delay, severe myopia, progressive chorioretinal dystrophy, facial anomalies, slender limbs with narrow hands and feet, tapered fingers, short stature, kyphosis and/or scoliosis, pectus carinatum, joint hypermobility, pes calcaneovalgus, and, variably, truncal obesity. Here, we describe the clinical and molecular findings in 14 patients from an isolated Greek island population. The clinical phenotype was fairly homogeneous, although microcephaly was not constant, and some patients had severe visual disability. All patients were homozygous for a novel intragenic COH1 deletion spanning exon 6 to exon 16, suggesting a founder effect. The discovery of this mutation has made carrier detection and prenatal diagnosis possible in this population.
BackgroundThe genetic background may influence methylmercury (MeHg) metabolism and neurotoxicity. ATP binding cassette (ABC) transporters actively transport various xenobiotics across biological membranes.ObjectiveTo investigate the role of ABC polymorphisms as modifiers of prenatal exposure to MeHg.MethodsThe study population consisted of participants (n = 1651) in two birth cohorts, one in Italy and Greece (PHIME) and the other in Spain (INMA). Women were recruited during pregnancy in Italy and Spain, and during the perinatal period in Greece. Total mercury concentrations were measured in cord blood samples by atomic absorption spectrometry. Maternal fish intake during pregnancy was determined from questionnaires. Polymorphisms (n = 5) in the ABC genes ABCA1, ABCB1, ABCC1 and ABCC2 were analysed in both cohorts.Results
ABCB1 rs2032582, ABCC1 rs11075290, and ABCC2 rs2273697 modified the associations between maternal fish intake and cord blood mercury concentrations. The overall interaction coefficient between rs2032582 and log2-transformed fish intake was negative for carriers of GT (β = −0.29, 95%CI −0.47, −0.12) and TT (β = −0.49, 95%CI −0.71, −0.26) versus GG, meaning that for a doubling in fish intake of the mothers, children with the rs2032582 GG genotype accumulated 35% more mercury than children with TT. For rs11075290, the interaction coefficient was negative for carriers of TC (β = −0.12, 95%CI −0.33, 0.09), and TT (β = −0.28, 95%CI −0.51, −0.06) versus CC. For rs2273697, the interaction coefficient was positive when combining GA+AA (β = 0.16, 95%CI 0.01, 0.32) versus GG.ConclusionThe ABC transporters appear to play a role in accumulation of MeHg during early development.
A battery of neurobehavioral examinations was carried out on 30 children who were 6-11 yr of age and who had resided near a lead smelter all their lives. Their blood lead levels were 35-60 micrograms/100 ml and erythrocyte protoporphyrin levels were greater than 100 micrograms/100 ml. Neurological examination revealed that they had a significantly higher incidence of pathological findings (e.g., muscle hypotonia, increased tendon reflexes, dysarthria, and dysdiadochokinesia) than children from an unpolluted area who were matched for age, sex, family size, and educational and socioeconomic status of the parents, but who had normal erythrocyte protoporphyrin levels. The children with elevated blood lead levels showed, after assessment by the Oseretsky test, retardation of motor maturation; they also scored higher on the minimal brain damage scale of the Rutter behavioral questionnaire. These differences persisted at a 4-yr follow-up, and their school performance was consistently poorer than that of the controls.
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