Study finds DNA markers linking season of birth to allergy risk

A team of researchers have discovered specific markers on DNA that link the season of birth to risk of allergy in later life, according to a study published Monday by the University of Southampton.

The team conducted epigenetic scanning on DNA samples from a group of people born on the Isle of Wight. They found that particular epigenetic marks were associated with season of birth and still present 18 years later.

The research team was also able to link these birth season epigenetic marks to allergic disease, for example people born in autumn had an increased risk of eczema compared to those born in spring. The results were validated in a cohort of Dutch children.

"We know that season of birth has an effect on people throughout their lives. For example generally, people born in autumn and winter are at increased risk for allergic diseases such as asthma. However, until now, we did not know how the effects can be so long lasting," said John Holloway, a professor at the University of Southampton and one of the study's authors.

"Epigenetic marks are attached onto DNA, and can influence gene expression for years, maybe even into the next generation. Our study has linked specific epigenetic marks with season of birth and risk of allergy. However, while these results have clinical implications in mediating against allergy risk, we are not advising altering pregnancy timing," said Holloway.

According to the study, further research is needed to understand what it is about the different seasons of the year that leads to altered disease risk, and whether specific differences in the seasons including temperature, sunlight levels and diets play a part.

More study is also needed on the relationship between DNA methylation and allergic disease, and whether other environmental exposures also alter the epigenome, with potential disease implications.

"Because season of birth influences so many things, the epigenetic marks discovered in this study could also potentially be the mechanism for other seasonally influenced diseases and traits too, not just allergy," said Dr Gabrielle Lockett at the University of Southampton, co-author of the study. Endit