Arsenic Toxicity - Genetic Architecture Plays A Role

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Academic Journal
Main Category: Water - Air Quality / Agriculture
Also Included In: Genetics;  Dermatology
Article Date: 24 Feb 2012 - 8:00 PST


PLoS Genetics reports that a large-scale genomic study in Bangladesh has found genetic variants that control arsenic metabolism and increase the risk of skin lesions in people chronically exposed to arsenic. The genetic variants that were found near the enzyme for metabolizing the chemical into a less toxic form are linked to the risk of developing arsenic-related disease according to the researchers from the University of Chicago, Columbia University, the International Center for Diarrheal Disease Research in Bangladesh, and the University of North Carolina.

Since the 1970s, when hand-pumped wells to access groundwater sources were installed, as many as 77 million people representing around half of Bangladesh's population, have been accidentally exposed to dangerous levels of arsenic. According to The World Health Organization, the exposure is "the largest mass poisoning of a population in history" (WHO, 2000).

Habibul Ahsan, and his team have studied the epidemiology of arsenic-related diseases, including skin lesions, diabetes, cardiovascular and respiratory illnesses as well as the effectiveness of interventions to prevent toxicity in this population for more than 10 years. In a quest to find out why some individuals seems to have a higher risk of developing disease after arsenic exposure, the new study decided to genotype almost 3,000 Bangladeshis for variants throughout the genome and discovered that genetic variants linked to arsenic metabolite levels and the risk of skin lesions in the region of a likely candidate gene is due to arsenite methyltransferase, an enzyme that is critical for arsenic metabolism.

After researchers examined the gene expression levels, they discovered that those same variants were linked to a reduced expression of the enzyme, and that boosting the arsenic metabolism could potentially be an effective intervention in those individuals exposed to the toxin and those with a high genetic risk from arsenic-related disease.

Ahsan concludes:

"These results add clarity to the genetic architecture that is playing a role in the arsenic toxicity and its underlying biological basis. It's an important study for a major problem affecting millions of people around the world, and it opens up opportunities for genetic studies of other major public health problems in developing countries."

Written by Petra Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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