Study finds genetic variants that increase risk of bedwetting

In a large-scale study of Danish children and youth, researchers at Aarhus University for the first time found genetic variants that increase the risk of bedwetting – commonly referred to as bedwetting or nighttime incontinence. The results provide completely new information about the processes in the body that cause this widespread phenomenon.

Researchers have long known that nocturnal incontinence is a highly inherited disease. Children who wet the bed at night often have siblings or parents who suffer or have suffered from the same condition. But so far, science has not been able to identify the genes involved.

In collaboration with the Danish research project iPSYCH and a team of international colleagues, researchers at Aarhus University have for the first time identified genetic variants that increase the risk of bedwetting. The results have just been published in the scientific journal The Lancet Child & Adolescent Health.

“As many as sixteen percent of seven-year-olds suffer from bedwetting and although many of them do, one to two percent of all young adults still have this problem. It is a serious illness that can negatively affect the self-esteem and well-being of children. For example, children may be afraid of being bullied and often withdraw from events involving overnight stays, ”says Jane Hvarregaard Christensen, one of the researchers behind the study.

Regulates urine production

In the study, the researchers looked at the genes of 3,900 Danish children and youth, who had been diagnosed with bedwetting or had taken medication for it. This group was then compared to 31,000 children and youth who did not suffer from the problem.

We have identified two locations in the genome where specific genetic variants increase the risk of bedwetting. The potential causative genes we signal play a role in ensuring that our brains develop the ability to reduce urine output at night, that bladder activity is regulated and recorded, and that we sleep appropriately, among other things. . “

Cecilie Siggaard Jørgensen, first author of the study

The study also shows that common genetic variants can explain up to a third of the genetic risk of bedwetting. This means that the genetic variants that we all have can lead to involuntary bedwetting, when they occur in a certain combination.

“But you can still have all of the variants without wetting the bed at night, because there are other risk factors involved that we haven’t mapped yet – both genetic and environmental. ‘is very complex and it is not possible to speak of a single gene responsible for nocturnal enuresis, ”explains Jane Hvarregaard Christensen.

Particularly vulnerable

The study also shows that children with many genetic variants that increase the risk of ADHD are particularly vulnerable to the development of bedwetting.

“Our results do not mean that ADHD causes bedwetting in a child, or vice versa, just that the two conditions have common genetic causes. Further research in this area will clarify the details of the biological differences and similarities between the two disorders, ”she points out.

As the study is a first-time study, the researchers also looked at more than 5,500 people from Iceland, where they found that the same genetic variants also appeared to increase the risk of bedwetting.

“This means we can be more certain that our results are not a coincidence. In the future, we want to know if the same genetic variants increase the risk of bedwetting in children in other parts of the world. Bedwetting is not only a problem in northern Europe, but affects millions of children around the world, ”she says.

Researchers hope they can further clarify the causes of bedwetting. It is very likely that it will be possible to identify even more genes and thus gain a better understanding of what is needed for a child to become dry at night.

“Right now we still can’t use a child’s genetic profile to predict, for example, whether the child will grow up out of shape or whether a particular treatment will work. This may be possible in the future when more detailed studies have been carried out. », Says Jane Hvarregaard Christensen.

Behind the results

The study is a so-called genome-wide association study (GWAS). By examining thousands of genetic variants distributed throughout the genome, a GWAS can reveal statistically significant correlations between specific genetic variants and nighttime incontinence in those examined.

The study is a collaboration between researchers from the Department of Biomedicine at Aarhus University and the Department of Pediatrics and Adolescent Medicine at Aarhus University Hospital. Researchers from the Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH and deCODE Genetics also contributed.