Johns Hopkins Bloomberg School of Public Health-led research team has pinpointed a region in the human genome associated with peanut allergy in children, offering strong evidence that genes can play a role in the development of food allergies. However, the scientists have stressed that genes are not the only players in food allergies, and there may be other molecular mechanisms that may contribute to whether those who are genetically predisposed to peanut allergies actually develop them.
Principal investigator, Xiaobin Wang, said, "We always suspected it, but this is the first genome-wide association study (GWAS) that identified a genetic link to well-defined peanut allergy."
Researchers analyzed DNA samples from 2,759 participants (1,315 children and 1,444 of their biological parents) enrolled in the Chicago Food Allergy Study; and scanned approximately 1 million genetic markers across the human genome, searching for clues to which genes might contribute to increased risk of developing food allergies, including peanut. They found that a genomic region harboring genes like HLA-DB and HLA-DR and located on chromosome six is linked to peanut allergy. These findings suggests that the HLA-DR and -DQ gene region probably poses significant genetic risk for peanut allergy as it accounted for about 20 percent of peanut allergy in the study population.
Researchers also found that not everyone with these mutations develops peanut allergy. They determined that epigenetic changes, in which a methyl group attaches itself to the DNA, alter the expression of a gene without altering its underlying code. The levels of DNA methylation regulates whether people with genetic susceptibility to the peanut allergy actually developed it.
Wang said, "While the study represents a good first step, more research is needed. For example, a better understanding of genetic susceptibility will allow for early risk assessment and prediction of food allergies, perhaps as early as in utero. Hopefully, one day, we can manage or prevent food allergies in a safe, simple, effective way. We might be able to use pharmaceutical treatment, but if we can figure out whether a lifestyle, nutrition or environmental change could reduce allergies, that would be even better."
The findings appear online in the journal 'Nature Communications'.