How our genes help link birth weight to adult illness

The study confirmed a link between low birth weight and adult height.

New research shows how genetics, not just environmental factors, play a role linking birth weight to adult health problems like diabetes.

It is no secret that underweight babies are more likely to suffer health problems like diabetes, heart disease or stunted growth.

For the most part, environmental factors like maternal smoking or poor health have been blamed but the new study, published today in the journal Nature Genetics, shows how genetic factors play a crucial role too.

The international study, which involved researchers from the University of Western Australia, examined genome data and follow-up study of 69,308 individuals from 43 studies.

The researchers were able to pinpoint several genetic signals that influence the risk of a baby developing diabetes and blood pressure problems later in life.

“By locating certain parts of the genome that are associated with birth weight and with those links to later disease, we have made the first steps to defining the precise biological processes that are involved,” said one of the researchers, Professor Mark McCarthy from the Oxford Centre for Diabetes, Endocrinology and Metabolism at the University of Oxford.

“In turn, such biological knowledge may play into better ways of treating and preventing adult disease.”

The study was also able to show how some genes help link low birth weight to diabetes but others associate high birth weight to diabetes.

“By highlighting some of the genetic regions involved, our work will help us to understand better the causes of these later life health outcomes,” said one of the study’s authors, Dr Rachel Freathy from the University of Exeter’s Peninsula College of Medicine and Dentistry.

Another author of the paper, Professor Marjo-Riitta Jarvelin, from the School of Public Health at the Imperial College London, said the study helped unpack the complex relationship between environmental and genetic factors contributing to a baby’s health risks.

“This paper clearly shows that same genetic variant that is determining fetal growth can also determine height growth and development of diseases like adult diabetes,” she said.

Professor Caroline Homer, Director of the Centre for Midwifery at the University of Technology Sydney, who was not involved in the study, said the relationship between genes and environmental factors highlighted the importance of good health in pregnancy and pre-pregnancy.

“In particular, smoking cessation before and during pregnancy, being of a healthy weight before and during pregnancy, avoiding alcohol in pregnancy and managing diabetes carefully if this occurs,” she said.

Professor Michael Chapman, head of the University of NSW’s School of Women’s and Children’s Health, said the results of the study were “not totally surprising since we have always recognised that children are the ‘ambassadors’ of their parents in their characteristics – for example, height, eye colour and tendencies towards familial recurrence of disease like diabetes, heart disease.”

“What this study now shows is the beginnings of the identification of the actual genes that make us so predisposed.The technology is awesome in terms of the complexity of the mapping processes and the informatics technology to extract the relevant data.”

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