BED WETTING GENE
By Sean Henahan, Access Excellence
COPENHAGEN The identification of a genetic marker for
nocturnal enuresis (bed-wetting) could lead to better diagnosis and treatment
of this common disorder, according to Danish researchers.
A team of Danish scientists examined 400 Danish families and selected
11 that suffered from 'primary nocturnal enuresis type 1' (PEN1). PEN1 is
characterized by three or more nightly episodes in children that are at
least seven years old, where the child has always had the problem.
The researchers observed that more than 90 percent of families with a
history of PNE expressed a specific genetic marker. They were able to localize
the responsible gene to the long arm of chromosome 13.
"A child who wets the bed does not do so on purpose," said
Hans Eiberg, Associate Professor at the Danish Center for Genome Research.
"We now have scientific evidence that many cases of bed-wetting are
caused by genetic factors beyond a child's and parent's control."
Identifying the gene responsible for nocturnal enuresis should greatly
facilitate the understanding and treatment of this emotionally debilitating
disorder. A variety of potential candidate genes have been named, including
genes involved in decreasing the amount of urine output during the night
and neuroreceptor genes that control such various activities as smooth muscle
contraction and sleep activity. However, none of these appear to lie in
the relevant region.
This is a significant development in the evaluation and treatment of
a condition that affects many children," said Marc Cendron, M.D., Pediatric
Urologist at Dartmouth-Hitchcock Medical Center. "Its impact will be
greatest for the estimated five to seven million American children above
age six who suffer from PNE. For such children, bed-wetting is a frustrating
condition which can be devastating to their self-esteem and very disruptive
to their family life."
A potential genetic component in PNE was proposed 20 years ago. Traditionally,
bedwetting among children has been considered a manifestation of emotional
problems. The current research is bound to change this perception. Recent
medical research has established a link between PNE and deficient production
of antidiuretic hormone (ADH), which controls urine production.
"There are two types of nocturnal enuresis. Primary enuresis, the
most prevalent, refers to children over the age of six who have never achieved
dryness for an extended period of time. Secondary enuresis, often associated
with emotional stress or medical illness, is the recurrence of bed-wetting
in children who have been dry for six months or longer.
"While we suspected PNE was hereditary, this is the first time a
direct genetic link has been identified," said Dr. Cendron. "I
believe the data in Nature Genetics may lay the groundwork for a large-scale
genetics study to identify the PNE gene."
Previous studies suggest that if both parents have a history of bed-wetting,
their children will have a 68 percent chance of being bed-wetters. If only
one parent was a bed-wetter, a child has a 44 percent chance of being a
bed-wetter. The studies also suggest only a 15 percent chance of a child
being a bed-wetter if neither parent has a history of the problem.
"Children with PNE often experience feelings of guilt and embarrassment.
This, compounded by a social stigma and misunderstanding of the condition,
often results in underdiagnosis, undertreatment, and needless suffering
by children and their families. In fact, a 1989 Journal of Pediatrics article
reports that 33 percent of parents deal with the condition by punishment
or humiliation. This is unfortunate. It is important that parents speak
to a physician about bed-wetting. There are safe and effective treatments
available," emphasized William Cromie, M.D., Chief, Section of Pediatric
and Reconstructive Urology and Vice Chairman, Department of Surgery, at
the University of Chicago.
"With the recognition of a genetic marker for enuresis, the approach
to treating PNE may be simplified," said Dr. Cromie. "Patients
may be identified and treated at an earlier age, which could spare them
the psychosocial effects that can result from this widespread and often
The Danish study appeared in the July 1, 1995 issue of the international
journal Nature Genetics.