The National Institutes of Health (NIH) has awarded Emory University scientists $2.8 million over four years to search for genes that predispose individuals to bipolar 1 disorder. Bipolar 1 disorder is a severe psychiatric illness that affects approximately one percent of the general population. More than 90 percent of cases can be attributed to inherited genetic variation, researchers believe.
Recent discoveries about structural variations in the human genome will help researchers with their quest, says principal investigator Stephen T. Warren, PhD, William P. Timmie Professor and chair of the Department of Human Genetics at Emory University School of Medicine.
"Although studies of families already have shown that genetic variations strongly influence predisposition to bipolar disease, traditional searches for causal genes have met with only limited success," says Warren. "Recently, we've found that a form of genetic variation called 'copy number variation,' which includes small deletions and duplications in the genome, is a prevalent and important form of genomic variation. New DNA technologies are allowing us to survey these variations and link them to disease."
The new study, in collaboration with investigators at Johns Hopkins School of Medicine, will examine the genomes of more than 1,000 individuals, including individuals with well-characterized cases of bipolar 1 disorder and their parents. The study also will examine the genomes of an additional group of 162 individuals of Ashkenazi Jewish descent with bipolar 1 disorder. Researchers will use state-of-art DNA arrays measuring more than two million points within the human genome.
The researchers also will compare genetic information from the current group of cases of bipolar 1 disorder to genetic information from a group of schizophrenia patients. Scientists believe bipolar 1 disorder and schizophrenia may not be distinct disorders and that they may include overlapping genetic variations.
"Our data will give us the potential to test the assertion that bipolar 1 disorder and schizophrenia are part of a continuum of psychiatric illness, and that copy number variation may predispose to psychiatric illness," says Warren.