"Finding a gene for bipolar disorder is like finding a needle in a haystack, but by focusing our search on families with a distinctive form of the illness we were able to pinpoint a region of the genome where disease genes are likely to be found," said James Potash, M.D., assistant professor of psychiatry at Johns Hopkins and lead author of a report on the study in the April issue of the American Journal of Psychiatry.
Although genes are unlikely to tell the whole story of major psychiatric diseases, the persistent frequency of mental illness in about 1 percent of the global human population, regardless of cultural or ethnic differences, and its tendency to run in families have always pointed to a strong genetic role. "But pinning down that role is complicated by the many variations in symptoms, even within the same family," says Potash. "There are probably many different genes and environmental factors that can cause any given mental illness."
Motivated by previous suggestions that certain broad regions of the DNA sequence, especially on human chromosomes 13 and 22, may contain genes that contribute to both bipolar disorder and schizophrenia, Potash and colleagues focused on those families with the psychotic form of bipolar disorder. Like bipolar disorder, psychotic bipolar disorder is characterized by see-sawing episodes of depression and mania, but it is distinctive because these mood changes often are accompanied by such psychotic symptoms as hallucinations and delusions.
The concept for the new study is that of two slightly overlapping circles, explains Potash. In one circle are all of the genes that con
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Contact: Trent Stockton
tstockt1@jhmi.edu
410-955-8665
Johns Hopkins Medical Institutions
1-Apr-2003