Our study, published in the journal, Nature Genetics on 1st May 2019 shows how the genetics of mother and baby shed light on links between birth weight and later health: https://go.nature.com/2vy40hv . This was a collaborative study led by researchers at the Universities of Exeter, Queensland, Oxford and Cambridge. We identified 190 associations between birth weight and specific parts of our DNA. Two-thirds of these had not been identified before, and for many of these associations, we can now say whether it s (i) direct effect of baby s genetics, or (ii) indirect effect of mother s genetics via the womb environment, or (iii) both. This is important because very small babies are at greater risk of birth complications and later-life risk factors e.g. high blood pressure (BP). Separating environmental effects of maternal genes from inherited baby effects enables us to test e.g. whether womb environment / genes / both contribute to higher later-life BP. We found that the low birth weight high BP relationship is complex, involving both genes and environment: high mother s BP causes lower birth weight, i.e. maternal environment effect. But NO evidence that mother s BW-lowering environment raises offspring BP. Rather, higher offspring BP is due to inherited genetic factors. An innovative statistical method made it possible to separate mother-baby effects in this well-powered sample. The wonderful UK Biobank and fantastic collaborations in the EGG consortium provided the power.
Understanding how maternal and fetal genetic and environmental factors influence offspring birth weight
We aim to identify genetic and environmental factors that are causally associated with birth weight. Both lower and higher birth weights in the normal range are observationally associated with a higher risk of type 2 diabetes in later life.
Birth weight is influenced by the maternal intrauterine environment, maternal genetics and fetal genetics. Both high and low birth weights have been associated with higher risk of type 2 diabetes in later life, but the causes of these associations are poorly understood. We aim to identify genetic and environmental factors that are causally associated with birth weight.
Mark I McCarthy, Rachel M Freathy, et al. Genome-wide associations for birth weight and correlations with adult disease, doi:10.1038/nature19806
|Lead investigator:||Rachel Freathy|
|Lead institution:||University of Exeter|