A cluster of genes may sway a person’s odds of becoming depressed, a new study shows. The findings may lead to new antidepressants.

The study appears online in Proceedings of the National Academy of Science’s early edition.

The researchers included Ma-Li Wong, MD, and Julio Licinio, MD, of the University of Miami’s Leonard M. Miller School of Medicine.

Wong, Licinio, and colleagues focused on 21 phosphodiesterase genes. Those genes govern the production of proteins that help cells -- including brain cells -- communicate with each other.

The researchers compared the genes of 284 Mexican-American adults diagnosed with major depression to 331 Mexican-Americans without major depression.

Certain gene variations were more common in the depressed participants, the study shows.

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Response to Antidepressants

The researchers also gave the antidepressants Prozac and Norpramin to participants with major depression for eight weeks.

During that time, people with certain phosphodiesterase gene variations responded better to those antidepressants.

Antidepressants are often very effective at treating depression, but some people may be better suited to some drugs than to others.

Currently, “there is no test or marker that tells you which person is more likely to respond to a specific drug,” Licinio says.

He calls the study’s findings “very novel,” since this family of genes hasn’t previously been studied for depression.

“We’re trying to identify who is more likely to have depression and to respond to antidepressants,” Licinio says. “This family of genes could become a new therapeutic target.”

The journal notes that Licinio and Wong have filed a patent based on the study’s findings.

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Expanding the Work

The study only included Mexican-Americans.

“Usually when people do research in minority populations, they do very small ‘me-too’ studies to see how a minority group responds to something, which has already been established in a larger population,” Licinio says.

“Somebody once told me catch-up is a game you can never win, so my approach has been different. This is the first study of its type and it was done in a minority population,” he adds.

Licinio and Wong, who are married to each other, formerly worked at the University of California, Los Angeles, where the participants were interviewed. The couple moved to the University of Miami in May, where they are broadening their pool of participants.

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By Miranda Hitti, reviewed by Louise Chang, MD

SOURCES: Wong, M. Proceedings of the National Academy of Sciences of the United States of America, early edition, week of Sept. 25-29, 2006. News release, University of Miami Leonard M. Miller School of Medicine.