Five distinct psychiatric disorders—autism, attention deficit-hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder and schizophrenia — may share some genetic risk factors, a new study finds.
During the study, researchers found four genetic markers
that may play a role in all five diseases. These markers were more
common in people with the one of the psychiatric disorders compared to
healthy people.
Two of these markers are found in genes thought to be involved in
balancing the level of calcium in brain cells, the researchers said.
(Calcium plays a role in many different cell functions, including
communication between cells.) Of these two markers, one has been
previously linked to bipolar disorder and depression, and the other to schizophrenia.
Although these five psychiatric disorders are thought of as separate
conditions, they share some symptoms. For instance, mood and thinking
problems can occur with schizophrenia, bipolar disorder and depression.
And children with ADHD often have symptoms of other developmental disorders, such as autism. In fact, a 2011 study detected genetic changes that were common to both ADHD and autism.
Because these psychiatric disorders share symptoms, researchers have
not always agreed on how to classify them. The new findings might one
day help researchers reclassify psychiatric conditions in a way that
incorporates genetics, the researchers said.
The new study will be published online Feb. 28 in the journal The Lancet.
To find the shared genetic markers, Dr. Jordan Smoller from
Massachusetts General Hospital in Boston and colleagues analyzed
information from 33,332 people who each had one of the psychiatric
disorders and 27,888 people who did not.
Because the study involved only people of European ancestry, it's not
clear whether the results apply to other populations as well. In
addition, the study only found an association between the four genetic
markers and these conditions, but cannot prove that the markers play a
role in causing the disorders. (That is, just because a person has one
of these markers, does not mean that he or she will develop a
psychiatric disorder.)
The findings confirm what many researchers already thought — that
genetic risk factors aren't necessarily specific to one disease, said
Dr. Joachim Hallmayer, an associate professor of psychiatry at Stanford University who was not involved with the study.
Some psychiatric disorders
already share some treatments, such as medications aimed at easing
symptoms. But genetic studies like these may reveal new targets for
drugs "that go more to the root of the condition and prevent the
condition," Hallmayer said.
However, more research is needed to determine how these genetic markers
cause problems that might lead to disease, Hallmayer said. Future
studies might investigate whether environmental factors could interact
with these genetic markers to trigger disease, he said.
Ellen Quillen, a geneticist at Texas Biomedical Research Institute in
San Antonio, said genetic studies that analyze several disorders at the
same time are important to identify the genetic risk factors these
various disorders share. Previously, evidence has shown that multiple
disorders run in the same family.
"I hope these results will encourage more researchers to look for
shared variants underlying clinically distinct disorders, as well as
focusing on particular shared symptoms," Quillen said.
Pass it on: Autism, ADHD, bipolar disorder, major depressive disorder and schizophrenia may share genetic risk factors. ( LiveScience.com )
No comments:
Post a Comment