February 23, 2012 -- One of the first large-scale genomic studies conducted in a developing country has discovered genetic variants that elevate the risk for skin lesions in people chronically exposed to arsenic. Genetic changes found near the enzyme for metabolizing the chemical into a less toxic form can significantly increase an individual's risk for developing arsenic-related disease.
The discovery could point the way to new screening and intervention options for people who are exposed to groundwater with high levels of arsenic, according to the investigators at the University of Chicago Medicine, Columbia University's Mailman School of Public Health, and in Bangladesh. The study is published in PLoS Genetics.
The group's genome-wide association study, or GWAS, was conducted in nearly 3,000 individuals exposed to arsenic for decades in Bangladesh. Since the widespread installation of hand-pumped wells to tap groundwater sources in the 1970s, as many as 77 million people about half the population of Bangladesh have been accidentally exposed to dangerous levels of arsenic. The World Health Organization calls the exposure "the largest mass poisoning of a population in history."
For more than a decade, the scientists have studied the epidemiology of arsenic-related disease, such as skin lesions, diabetes, and respiratory illnesses, in this population, as well as the effectiveness of interventions to prevent toxicity. In the new study, the researchers sought genetic answers for why some individuals appear to be at higher risk for developing disease after arsenic exposure.
"These results add clarity to the genetic architecture that is playing a role in arsenic toxicity and its underlying biology," said senior author Habibul Ahsan, MD, MMedSc, Louis Block Professor of health studies, medicine and human genetics at the University of Chicago Medicine. "It's a rare type of study for a major problem affecting millions of pe
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Columbia University's Mailman School of Public Health