Thursday, July 31, 2008

Gene-Hunters Find Hope and Hurdles in Schizophrenia Studies

Two groups of researchers hunting for schizophrenia genes on a larger scale than ever before have found new genetic variants that point toward a different understanding of the disease.

The variants discovered by the two groups, one led by Dr. Kari Stefansson of Decode Genetics in Iceland and the other by Dr. Pamela Sklar of Massachusetts General Hospital, are rare. They substantially increase the risk of schizophrenia but account for a tiny fraction of the total number of cases.

This finding, coupled with the general lack of success so far in finding common variants for schizophrenia, raises the possibility that the genetic component of the disease is due to a large number of variants, each of which is very rare, rather than to a handful of common variants.

“What is beginning to emerge is that a lot of the risk of brain diseases is conferred by rare deletions,” Dr. Stefansson said. The three variants discovered by his group and Dr. Sklar’s involve the deletion of large sections of DNA from specific sites in a patient’s genome.


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