Study reveals value of schizophrenia-related gene variation

February 13, 2007

University of Iowa researchers have learned more about a genetic variation that is a small risk factor for a mild form of schizophrenia yet also is associated with improved overall survival.

The findings, which appear online in the American Journal of Medical Genetics, could help lead to treatments for schizophrenia and even other illnesses, and ways to leverage the gene variation's advantages. An abstract of the article is available at http://www3.interscience.wiley.com/cgi-bin/abstract/114112711/ABSTRACT.

This HOPA12pb gene variation advance drew on a genetic database that was about five times larger than sample sizes used in previous research, said Robert Philibert, M.D., Ph.D., associate professor of psychiatry in the UI Roy J. and Lucille A. Carver College of Medicine and the study's co-author.

"The study used the National Institute of Mental Health's largest publicly available sample, and thus it provides even more convincing evidence that the gene variation is worth studying," Philibert said.

The genetic variation causes a change in the portion of the protein that regulates the development of dopamine-releasing neurons. Antipsychotic drugs work by blocking dopamine, but drug treatments have limited success, and so scientists seek other ways to treat patients.

The team analyzed the genetic data of 900 European-Americans and found the HOPA gene variation in 22 individuals. Although the gene variation accounts for only an estimated .3 percent of all schizophrenia, nearly three of every 100 Caucasians have the gene variation.

"Most mutations associated with psychosis are found in only one in 10,000 or one in 100,000 individuals, and so these mutations do not lend themselves as study models," Philibert said. "HOPA is a relatively common mutation and that makes it valuable to study."

Philibert said that because HOPA often is a helpful gene variant, the fact that it sometimes is not reveals that it can react with environmental or other genetic factors to result in illness.

"If we can find a way to intervene in those interactions, then we may be able to avert disease and harness how this gene variation may help us," Philibert added.

In a current phase I, or safety, clinical trial, UI researchers are treating an individual who has a HOPA gene variation for symptoms of underactive thyroid.

"We don't know if this hypothyroidism is a direct effect of the gene or a genetic-environmental interaction," Philibert said. "We are using thyroid hormone supplementation to target the symptoms."

The UI Research Foundation and the National Institutes of Health (NIH) share a patent for HOPA12pb, which is found on the X-chromosome. Men are more likely than women to have this form of schizophrenia because it is X-linked. However, only about one in 30 men with the HOPA gene variation has schizophrenia.
-end-
The study was funded in part by the National Institutes of Health. Donald Black, M.D., UI professor of psychiatry, was a co-author, and other UI experts in psychiatry and neurosciences also contributed to the research.

HOPA stands for Human Opposite Paired Element (the last two letters in the abbreviation are taken from the first two letters in the word "Paired.")

A UI news release on previous HOPA research is available online at: http://www.news-releases.uiowa.edu/2004/april/041204schizophrenia.html

STORY SOURCE: University of Iowa Health Science Relations, 5137 Westlawn, Iowa City, Iowa 52242-1178

MEDIA CONTACT: Becky Soglin, 319-335-6660, becky-soglin@uiowa.edu

University of Iowa

Related Schizophrenia Articles from Brightsurf:

Schizophrenia: When the thalamus misleads the ear
Scientists at the University of Geneva (UNIGE) and the Synapsy National Centre of Competence in Research (NCCR) have succeeded in linking the onset of auditory hallucinations - one of the most common symptoms of schizophrenia - with the abnormal development of certain substructures of a region deep in the brain called the thalamus.

Unlocking schizophrenia
New research, led by Prof. LIU Bing and Prof. JIANG Tianzi from the Institute of Automation of the Chinese Academy of Sciences and their collaborators have recently developed a novel imaging marker that may help in the personalized medicine of psychiatric disorders.

Researchers discover second type of schizophrenia
In a study of more than 300 patients from three continents, over one third had brains that looked similar to healthy people.

New clues into the genetic origins of schizophrenia
The first genetic analysis of schizophrenia in an ancestral African population, the South African Xhosa, appears in the Jan.

Dietary supplement may help with schizophrenia
A dietary supplement, sarcosine, may help with schizophrenia as part of a holistic approach complementing antipsychotic medication, according to a UCL researcher.

Schizophrenia: Adolescence is the game-changer
Schizophrenia may be related to the deletion syndrome. However, not everyone who has the syndrome necessarily develops psychotic symptoms.

Study suggests overdiagnosis of schizophrenia
In a small study of patients referred to the Johns Hopkins Early Psychosis Intervention Clinic (EPIC), Johns Hopkins Medicine researchers report that about half the people referred to the clinic with a schizophrenia diagnosis didn't actually have schizophrenia.

The ways of wisdom in schizophrenia
Researchers at UC San Diego School of Medicine report that persons with schizophrenia scored lower on a wisdom assessment than non-psychiatric comparison participants, but that there was considerable variability in levels of wisdom, and those with higher scores displayed fewer psychotic symptoms.

Recognizing the uniqueness of different individuals with schizophrenia
Individuals diagnosed with schizophrenia differ greatly from one another. Researchers from Radboud university medical center, along with colleagues from England and Norway, have demonstrated that very few identical brain differences are shared amongst different patients.

Resynchronizing neurons to erase schizophrenia
Today, a decisive step in understanding schizophrenia has been taken.

Read More: Schizophrenia News and Schizophrenia Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.