Do Mothers’ and Babies’ Genes Influence Birth Weight?

May 20 2019

Do Mothers’ and Babies’ Genes Influence Birth Weight?

The Findings:

An international research team conducted a large study and learned that genetic factors from both mothers and babies interact to influence birth weight. The researchers identified 190 genetic signals from variants affecting birth weight, of which 129 signals were new discoveries. The researchers also demonstrated that some of the mother’s genes were not inherited by the baby, but they did influence the baby’s uterine environment during pregnancy.

Why it matters: 

Size at birth influences diseases in later life. Analyzing how genes from both mothers and babies affect a child’s birth weight is important because relatively high or low birth weights are known to track with an increased lifelong effect on health, raising risks of high blood pressure and metabolic diseases, such as type 2 diabetes. The new findings may allow researchers to devise novel intervention strategies to alleviate such risks.

Who conducted the study: 

The study involved more than 200 scientists from 20 nations in the Early Growth Genetics (EGG) Consortium, including three CHOP genetics researchers: Hakon Hakonarson, MD, PhD, director of the Center for Applied Genomics (CAG) at Children’s Hospital of Philadelphia; Struan F. A. Grant, PhD, co-director of Center for Spatial and Functional Genomics at CHOP; and Diana L. Cousminer, PhD, a geneticist at CHOP. Rachel M. Freathy, PhD, of the University of Exeter, U.K., and four colleagues, from the Universities of Cambridge, Oxford and Bristol, co-led the study.

How they did it: 

The study team performed genome-wide association studies and other analyses of genetic data from 200,000 mothers, as well as birth weights of their children, along with genetic data and birth weights from 321,000 individuals from the UK Biobank and the EGG Consortium. CHOP contributed a substantial collection of trans-ethnic pediatric data from CAG. The team used novel statistical techniques to separate the respective contributions of the mothers’ genes and the babies’ genes to the babies’ birth weight.

Quick thoughts: 

“The current study supports the importance of optimizing maternal-fetal health so that newborns have the healthiest birth weight possible,” Dr. Grant said.  He added that improvements in care may draw on future medical interventions using a precision medicine approach informed by knowledge of prenatal genetic influences. Such approaches align with CHOP’s Lifespan Initiative, aimed at discovering early life interventions that can improve health in adolescence and adulthood.

What’s next: 

Future research in this area will include longitudinal analyses over a longer time course, investigating childhood obesity and growth during puberty, a specific focus of Dr. Cousminer. 

“Because both intrauterine and postnatal growth trajectories may affect health outcomes later in life, future work should focus on a lifelong view to maximizing health,” Dr. Cousminer said.

Where the study was published:

The study “Maternal and fetal genetic effects on birth weight and their relevance to cardio-metabolic risk factors” appeared online in Nature Genetics.

Where to learn more:

Get more details on CHOP News, and read the University of Exeter press release about this study.