DNA linked to pre-eclampsia during pregnancy

DNA and pre-eclampsia, posted by Tanja Mathiesen Wibe

The genes decide

What causes pre-eclampsia during pregnancy? The answer lies in the mother’s DNA. And perhaps in the child’s father’s.

Pre-eclampsia is one of the leading causes of morbidity and mortality in pregnant women in the West. In Norway, three per cent of all pregnant women are affected by the disease.

There is no cure for pre-eclampsia. And the reasons why some women develop pre-eclampsia and others do not, remains unknown.

Now, researchers at NTNU have discovered genetic differences between women who have had pre-eclampsia and women who have not. They have found four genes that are likely to play a role in development of this condition.

Assessed 25 genes

The Nord-Trondelag Health Study (HUNT), a database that contains individual health and family information from approximately 120,000 people, supplied the researchers with DNA from 1139 women who have been affected by pre-eclampsia, and from 2269 women who have not been affected.

All told, 186 gene variants in 25 different genes were tested by PhD candidate Linda Tømmerdal Roten and her colleagues. The researchers found four genes in the affected women where single gene variations were more or less prevalent than among the unaffected women.

In addition, researchers found a gene on chromosome 2 that had previously been identified as risk factor and has now been confirmed as such.

Similar studies have been conducted on families in Australia, where researchers also found chromosomal variations in women with pre-eclampsia.

Cure in sight?

Tømmerdal Roten hopes that an understanding of the differences between the genes of sick and healthy women will eventually lead to drugs that can affect protein processes in the body. With time, it’s possible that there could be a cure for pre-eclampsia. But predicting exactly when is another matter altogether, the researcher says.

“Pre-eclampsia may be prevented to a limited degree if the cause is found in the genes. But a survey of risk groups will be able to help women to get extra careful monitoring during pregnancy,” she says.

The families – and the father’s role

Previously, Tømmerdal Roten and her colleagues have only studied the mother’s role in the illness. Now they are planning a new study that will include a larger part of the family and that may be the largest of its kind.

The new study involves 426 women who all have had pre-eclampsia, who have been invited back to the maternity ward for an interview and a blood test. They are being encouraged to bring all kinds of relatives: children, parents, siblings and cousins. The purpose is to study the same genes in people with and without pre-eclampsia in the same family.

The women are also being encouraged to bring the child’s father, because there is now strong evidence that the father’s genetic contribution plays a role. Not many researchers have looked at this possibility, and certainly not on the scale that the family study will make possible.

Complete mapping

The researcher also wants to survey all of the genetic material from women from the HUNT study and from the Norwegian Mother and Child Cohort Study. This will provide a complete picture of the genes that might play a role in the development of this serious condition.

“We will then map out the functions of genes, the processes they are involved in and what link they have to other diseases,” Tømmerdal Roten.

“Now it also appears that we will be able to map the entire genetic material from both the child’s father and the child. This will provide a much more complete picture of which genes are involved. It’s likely that different genes from the mother and father contribute to pre-eclampsia. And by looking at the child’s genes as well, we can look at the interaction between the parents’ and child’s genes.

Photo: She knows her subject. Linda Tømmerdal Roten defended her doctorate in August, five weeks before she was due to give birth. Photo credit: Thor Nielsen

Tanja Mathiesen Wibe is employed by the Norwegian University of Science and Technology, the Information division. She works with alumni relations and also writes science news articles.