Arsenic toxicity may vary, depending on genes


NEW YORK (Reuters Health) - Some children with particular genetic patterns appear to process arsenic differently, suggesting that they may be more -- or less -- vulnerable to its effects, according to new study findings.


Researchers found that children who carry a certain variation of the CYT19 gene tend to break down arsenic differently than children with different variations of the same gene.

"If people metabolize arsenic differently," Dr. Walter T. Klimecki told Reuters Health, "it's reasonable to suspect they may have a different risk of toxicity." If that's the case, "then the regulators need to consider regulating with that in mind" -- perhaps by capping acceptable levels at what's safe for the more vulnerable group, not the population at large, he added.

Klimecki, of the University of Arizona at Tucson, explained that arsenic has always posed somewhat of a "conundrum" for researchers. A significant body of "unequivocal" evidence shows it can cause cancer and other health problems, but researchers remain unclear about how arsenic does its damage, the researcher noted.

To understand more how people respond to arsenic, Klimecki and his colleagues collected urine samples from 139 people whose drinking water contained a range of arsenic concentrations, from very little to amounts that approached the current upper U.S. limit for arsenic in drinking water.

Reporting in the journal Environmental Health Perspectives, the investigators found that children who carried one particular variant in the CYT19 gene -- which investigators have linked to arsenic metabolism -- showed different amounts of arsenic breakdown products in their urine, suggesting that they metabolized the chemical differently.

Whether that means those children are more or less susceptible to arsenic is unclear, Klimecki noted.

Interestingly, variants in the CYT19 gene appeared to have no relationship to how adults metabolized arsenic, suggesting that the CYT19 gene may be more active in childhood, then gets turned off in adulthood, Klimecki noted.