Mother's environment before conception may affect her child's life long risk of disease

http://www.eurekalert.org/pub_releases/2015-06/lsoh-meb060815.php

Public Release: 10-Jun-2015
London School of Hygiene & Tropical Medicine

Scientists have shown for the first time that a mother's environment around the time of conception could permanently change the function of a gene influencing immunity and cancer risk in her child.

Diet is likely to play a role in this process, according to the study published in Genome Biology.

This is the latest discovery by an international collaboration led by researchers at the Medical Research Council (MRC) Unit, based in The Gambia, West Africa, and the MRC International Nutrition Group at the London School of Hygiene & Tropical Medicine together with a team at Baylor College of Medicine in Houston, Texas.

Previous studies by the scientists showed that a child's DNA can be affected by their mother's diet before pregnancy [1] but they have now hit upon a gene called VTRNA2-1 as being particularly sensitive to these changes. VTRNA2-1 is a tumour suppressor gene which also affects how the body responds to viral infections.

It is well established that small differences in the DNA that makes up our genes can affect our risk of having a range of diseases. While a child's genes are inherited directly from their parents, how these genes are expressed is controlled through 'epigenetic' modifications to the DNA. The most commonly studied epigenetic modifications are chemical marks (methylation) placed on the DNA of genes that can prevent the message from being read; like sleepers laid across a railway track. Importantly, these marks can be influenced by an individual's environment.

•••••

The Gambian data comes from a unique "experiment of nature" where the population's dependence on own grown foods and a markedly seasonal climate impose large differences in diet and other environmental factors between rainy ('hungry') and dry ('harvest') seasons.

•••••

Prior evidence concerning the VTRNA2-1 gene suggests that the observed epigenetic changes could affect an individual's ability to fight viral infections (such as influenza) but reciprocally alter its tumour suppressor activity and possibly offer protection against certain cancers (so far shown for acute myeloid leukaemia, lung and oesophageal cancers).

•••••

"Our next step is to follow Gambian children to test exactly how epigenetic differences in the VTRNA2-1 gene affect gene expression and life-long health. This could help shed light on longstanding questions such as why mortality rates due to infection are higher in Gambians born in the rainy season."