Researchers Find Genetic "HOT SPOTS" Of Manic-Depression

INDIANAPOLIS-- The largest linkage sample to date for bipolar illness has been completed in a collaborative effort by researchers who say the information may have a large impact on treatment of the disease which affects thousands of Americans.

The National Institute of Mental Health Genetics Initiative Bipolar Group is composed of researchers from Indiana University, John Hopkins University, the National Institute of Mental Health Intramural Research Program and Washington University. The group is chaired by John Nurnberger Jr., M.D., director of the Institute of Psychiatric Research at the Indiana University School of Medicine.

Manic-depression, also known as bipolar affective disorder, is characterized by severe swings in high and low mood states that generally last weeks or months. It is estimated to affect 3 percent of Americans. Approximately 75 percent of all manic-depressives have at least one close relative with manic-depression or severe depression.

"We are finding areas on several different chromosomes that seem to be important for bipolar disorder, not only chromosomes 18 and 21, which were reported before, but also 1, 6, 7, 10 and possibly some other areas, said the group's chairman, John Nurnberger Jr., M.D., director of the Indiana University Institute for Psychiatric Research.

"This seems to be a very complex condition, genetically. However, the sample sizes we are able to study now give us hope for sorting out the different types of bipolar illness in terms of their specific chemical causes, and in the future developing treatments targeted to each type," he added.

Nurnberger is a psychiatrist who treats many manic-depressive patients, in addition to chairing this long-term research project.

In a paper published in Neuropsychiatric Genetics, the group reports initial data from a genomic survey of 540 individuals from 97 families; 230 of the individuals suffered from Bipolar I, the most severe form of manic-depression. The majority of families had at least one affected sibling pair.

As with hypertension, diabetes and Alzheimer's disease, bipolar disease is thought to involve more than one gene. The new studies provide powerful evidence for complex inheritance and evidence against single-gene explanations.

The research group is composed of researchers from Indiana University, Johns Hopkins University, the National Institute of Mental Health Intramural Research Program and Washington University. The group continues to investigate the genetics of bipolar disorder and is currently studying a second large group of families to try to confirm their initial results.

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