Low Birth Weight and Diabetes Have a Common Genetic Background

Low birth weight increases the risk of developing Type 2 diabetes later in life. Until recently scientists had attributed this to maternal malnutrition during pregnancy. However, now it seems that genetic background may also play a major role. 

A research team has now demonstrated, that gene variants which influence insulin metabolism can also affect birth weight.

In the BABYDIAB study led by Professor Anette Gabriele Ziegler, at the University of Technology Nunchen, researchers analyzed the data of 729 children whose mothers had Type 1 diabetes and who thus had a higher diabetes risk.

The scientists investigated the genetic background of fetuses for alterations in individual DNA bases, termed single nucleotide polymorphisms (SNP’s). Here they focused on three gene regions which are known to be risk alleles for diabetes caused by reduced insulin secretion. They looked at these in relation to birth weight.

It turned out that there was a significant association between the two SNP’s of the HHEX-IDE gene region and low birth weight. This was independent of HbA1c levels (long-term blood glucose levels) of the expectant mother, indicating a lesser correlation between maternal nutrition and blood glucose regulation. “Interestingly, we found this effect in children whose mothers had Type 1 diabetes. This could mean that an a priori reduced insulin secretion also plays a role in the development of autoimmune Type 1 diabetes,” explained Dr. Christiane Winkler, author of the publication.

In contrast, the researchers found no correlation between the two SNP’s of the other gene regions that were studied (CDKAL1 and SLC30A8) and birth weight. However, this does not entirely exclude an association and such an effect could become apparent with higher numbers of participants. “Indications of genetic associations are usually only found in very large populations. As we see here, it is important to substantiate these in smaller, but very well-phenotyped study populations. We can thus gain information about the possible mechanism of the original results,” emphasized P.D. Dr. Thomas Illig, head of the Epidemiology Biological Samples Genomics research unit at Helmholtz Zentrum München.

With their findings, the Munich researchers have come a step closer to understanding the underlying genetic mechanisms of diabetes diseases. “Next, we want to investigate whether the genetic associations observed in this study could also have an effect on body weight later in life. Due to the long-term BABYDIAB study, which has run continuously since 1989, this data already exists,” Dr. Winkler explained.

Helmholtz Zentrum Muenchen