Center for Children's Environmental Health Manuscript Selected as Editor's Choice

Chamacos Project

An article by investigators from the Center for Children's Environmental Health published in the journal Environmental and Molecular Mutagenesis was selected as the Editor's Choice by the Environmental Mutagen Society. To honor its scientific contribution, the journal featured it on the front cover for March 2011.

"Effects of PON Polymorphisms and Haplotypes on Molecular Phenotype in Mexican-American Mothers and Children" was co-authored by Karen Huen, Lisa Barcellos, Kenneth Beckman, Sherri Rose, Brenda Eskenazi and Nina Holland. Researchers investigated how individual changes in the paraoxonase (PON) genes relate to variation of PON1 enzymatic activity. Since the PON1 enzyme can metabolize some neurotoxic organophosphate pesticides, these genetic variants may affect an individual's susceptibility to pesticide exposure.

Huen and colleagues carried out a thorough analysis of PON genetic variation by sequencing the PON1 gene in 30 Mexican-American subjects.  More than 90 PON genetic variants were identified, including 9 novel polymorphisms.

Researchers also assessed the functional significance of these genetic variants in over 700 Mexican-American mothers and children from the CHAMACOS birth cohort study from Salinas Valley, California. Such information is critical for identifying populations particularly vulnerable to organophosphate pesticide exposure.  For instance, individuals with genetic polymorphisms known to code for lower PON1 enzymatic activity may be considered at increased risk of adverse health outcomes when exposed to organophosphate pesticides.

Allele frequencies of many of the genetic variants were noticeably different in the Mexican-American subjects compared to frequencies reported in Caucasian populations that may reflect potential ethnic differences in response to exposures.

The investigators also demonstrated that paraoxonase phenotypes are not static. The relative contribution of certain PON1 polymorphisms was higher in mothers than newborns, suggesting that the role of genetic variants on susceptibility to pesticide exposure changes with age.

Their research was supported by grants from the U.S. Environmental Protection Agency (R826886, R82670901) and the National Institute of Environmental Health Science (R01ESO12503-03, PO1 ES009605). 

Article adapted from an announcement by the Environmental Mutagen Society
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