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Environmental Factor

November 2011

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EMS honors NIEHS-funded researcher

By Ian Thomas
November 2011

left to right, Nina Holland, Ph.D. and Karen Huen, Ph.D.

Holland, left, and Huen are shown at the UC Berkeley graduation ceremony in 2009. (Photo courtesy of Karen Huen)

Center For The Health Assessment Of Mothers And Children Of Salinas (CHAMACOS) poster

Center For The Health Assessment Of Mothers And Children Of Salinas. Center of Excellence in Children's Environmental Health. University of California, Berkeley.

The Environmental Mutagen Society (EMS) has selected “Effects of PON polymorphisms and haplotypes on molecular phenotype in Mexican-American mothers and children,” a study from Karen Huen, Ph.D., as its top publication of 2011 from a student or new investigator. Backed by joint funding from NIEHS and the U.S. Environmental Protection Agency (EPA), the study( Exit NIEHS explores the genetic differences between Mexican-American and Caucasian mothers and children with regard to the effects of paraoxonase (PON), a protective metabolic enzyme that can detoxify some organophosphate pesticides (OPs). 

“I'm sincerely grateful to EMS for continuing to recognize and encourage the work of new investigators like myself,” said Huen, an assistant researcher with the Center for Children's Environmental Health Research at the University of California (UC), Berkeley and the paper's first author. “It's an incredible honor to receive this award.”

Nina Holland, Ph.D., the study's lead researcher, credited her fellow scientists from UC Berkeley for much of the project's success. Study participants were drawn from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal birth cohort study funded by a grant( Exit NIEHS from NIEHS.

“None of this would have been possible without the hard work and dedication of our fellow investigators, students, and staff at the Center for Environmental Research and Children's Health (CERCH)( Exit NIEHS, some of whom have followed this cohort for more than 10 years.”

Linking age and ethnicity to disease susceptibility

By resequencing PON genes in 30 children and mothers from the Salinas Valley in California, followed by high-throughput genotyping and haplotype analyses for more than 400 mother-child pairs, Huen and her team identified a total of 90 genetic variants, many of which were novel, functionally significant, and noticeably varied from their Caucasian counterparts.

“Initially, we expected to see the effects of some PON genetic polymorphisms on the quantity and efficiency of organophosphate detoxification,” explained Holland. “In the end, we found that, in the case of exposure, children in some populations remain more vulnerable than adults until nearly 9 years of age, [and] some of them may be more than 50 times more susceptible than others due to their genetic makeup.”

The whole picture

While the results of this study clearly indicate that PON status can influence levels of susceptibility among various population and age groups, Huen and Holland are quick to point out that several additional factors should be examined when evaluating new ways to protect the public from pollutants like OPs. 

“Many emerging public health problems, such as childhood obesity and neurodevelopment issues, may be the result of prenatal or adolescent exposures to environmental pollutants,” Holland explained. “At the same time, it's also essential for future research to factor additional parameters, such as diet and lifestyle, when determining the overall impact on the health of a given population.”

A collective effort

Still, researchers insist that joint partnerships between like-minded organizations will ultimately be the key to beneficial research moving forward.

“This is the age of genomics and personalized medicine,” Holland observed. “Partnerships, like the one between NIEHS and EPA which funded this study, will be crucial in producing the kind of research that can actually shape policy and protect children and pregnant women from the harmful effects of substances such as OPs.”

Since its founding in 1969, EMS has been dedicated to the promotion of critical research into the causes and consequences of damage to the genome and epigenome, for the purpose of ensuring a healthy, sustainable environment for future generations. Visit the EMS website( Exit NIEHS to learn more.

Citation: Huen K, Barcellos L, Beckman K, Rose S, Eskenazi B, Holland N.( Exit NIEHS 2011. Effects of PON polymorphisms and haplotypes on molecular phenotype in Mexican-American mothers and children. Environ Mol Mutagen 52(2):105-116.

(Ian Thomas is a public affairs specialist with the NIEHS Office of Communications and Public Liaison.)

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