pesticides as a cause of autism

[Guest guest]

I think Shattock was considering OP-poisoning as a reason why

chelation might work for people with no evidence of heavy metal poisoning

Sally

> 3. */Paraoxonase gene variants are associated with autism in North

> America, but not in Italy: possible regional specificity in

> gene-environment interactions/*

>

> D'Amelio M et al.

> Mol Psychiatry. 2005 Nov;10(11):1006-16.

>

> Organophosphates (OPs) are routinely used as pesticides in agriculture

> and as insecticides within the household. Our prior work on Reelin and

> APOE delineated a gene-environment interactive model of autism

> pathogenesis, whereby genetically vulnerable individuals prenatally

> exposed to OPs during critical periods in neurodevelopment could

> undergo altered neuronal migration, resulting in an autistic syndrome.

> Since household use of OPs is far greater in the USA than in Italy,

> this model was predicted to hold validity in North America, but not in

> Europe. Here, we indirectly test this hypothesis by assessing

> linkage/association between autism and variants of the paraoxonase

> gene (PON1) encoding paraoxonase, the enzyme responsible for OP

> detoxification. Three functional single nucleotide polymorphisms, PON1

> C-108T, L55M, and Q192R, were assessed in 177 Italian and 107

> Caucasian-American complete trios with primary autistic probands. As

> predicted, Caucasian-American and not Italian families display a

> significant association between autism and PON1 variants less active

> in vitro on the OP diazinon (R192), according to case-control

> contrasts (Q192R: chi2=6.33, 1 df, P<0.025),

> transmission/disequilibrium tests (Q192R: TDT chi2=5.26, 1 df,

> P<0.025), family-based association tests (Q192R and L55M: FBAT Z=2.291

> and 2.435 respectively, P<0.025), and haplotype-based association

> tests (L55/R192: HBAT Z=2.430, P<0.025). These results are consistent

> with our model and provide further support for the hypothesis that

> concurrent genetic vulnerability and environmental OP exposure may

> possibly contribute to autism pathogenesis in a sizable subgroup of

> North American individuals.

>

>

> 4. */Maternal residence near agricultural pesticide applications and

> autism spectrum disorders among children in the California Central

> Valley/*

>

> EM et al.

> Environ Health Perspect. 2007 Oct;115(10):1482-9.

> http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=2022638 & blobtype=pdf

>

> BACKGROUND: Ambient levels of pesticides ( " pesticide drift " ) are

> detectable at residences near agricultural field sites. OBJECTIVE: Our

> goal was to evaluate the hypothesis that maternal residence near

> agricultural pesticide applications during key periods of gestation

> could be associated with the development of autism spectrum disorders

> (ASD) in children. METHODS: We identified 465 children with ASD born

> during 1996-1998 using the California Department of Developmental

> Services electronic files, and matched them by maternal date of last

> menstrual period to 6,975 live-born, normal-birth-weight, term infants

> as controls. We determined proximity to pesticide applications using

> California Department of Pesticide Regulation records refined using

> Department of Water Resources land use polygons. A staged analytic

> design applying a priori criteria to the results of conditional

> logistic regressions was employed to exclude associations likely due

> to multiple testing error. RESULTS: Of 249 unique hypotheses, four

> that described organochlorine pesticide applications--specifically

> those of dicofol and endosulfan--occurring during the period

> immediately before and concurrent with central nervous system

> embryogenesis (clinical weeks 1 through 8) met a priori criteria and

> were unlikely to be a result of multiple testing. Multivariate a

> posteriori models comparing children of mothers living within 500 m of

> field sites with the highest nonzero quartile of organochlorine

> poundage to those with mothers not living near field sites suggested

> an odds ratio for ASD of 6.1 (95% confidence interval, 2.4-15.3). ASD

> risk increased with the poundage of organochlorine applied and

> decreased with distance from field sites. CONCLUSIONS: The association

> between residential proximity to organochlorine pesticide applications

> during gestation and ASD among children should be further studied.

>

>