Gestational diabetes shares strong genetic links with type 2 diabetes

New evidence has emerged showing that diabetes developed during pregnancy is likely an early manifestation of type 2 diabetes, triggered by the stresses pregnancy places on the body.

In the largest study of its kind, University of Queensland researchers collaborated with the Genetics of Diabetes In Pregnancy (GenDIP) Consortium to analyse data from more than 38,000 women with gestational diabetes and 776,000 without the condition, finding significant genetic similarities between the 2 conditions.

PhD candidate Caroline Brito Nunes (pictured) at UQ’s Institute for Molecular Bioscience said the research identified 37 genetic variants associated with gestational diabetes, 7 of which had not been previously reported.

“Almost all of these genetic variants overlapped with those linked to type 2 diabetes,” Ms Brito Nunes said.

“We also discovered that some of these variants appear to have stronger effects on diabetes specifically during pregnancy, and found evidence that genetic effects might differ across populations.”

Gestational diabetes affects about 14 per cent of pregnancies and can lead to serious complications including overly large babies, obstructed labour, preterm deliveries, and health risks for both mother and child.

Women who have had gestational diabetes face an 8 to 10-fold increased risk of developing type 2 diabetes later in life, with environmental factors including obesity also playing a part.

Professor David Evans said as gestational and type 2 diabetes were becoming more common and straining health systems across the world, greater understanding of the conditions was needed.

“A key question in the field has been: do they actually represent different conditions or is it the same underlying disease and just the stresses of pregnancy making type 2 diabetes manifest a bit earlier?” Professor Evans said.

“This work has shown that to a large extent they are genetically very similar, with a small genetic component that may be pregnancy specific.”

The study included people from European, East Asian, South Asian, African and Hispanic backgrounds, making it the most diverse genetic study of gestational diabetes to date.

Dr Gunn-Helen Moen said a much larger study with millions of participants is already underway to better understand the genetic drivers and include more diverse populations.

“Our study has identified evidence of genuine ancestry-related differences, and this is something that we will examine further in our larger study,” Dr Moen said.

The study is published in Nature Communications.