STEVE INSKEEP, HOST:
Different neurological conditions - conditions like autism, schizophrenia and bipolar disorder - appear to have more in common than we might have thought. NPR's Merrit Kennedy reports.
MERRIT KENNEDY, BYLINE: Brain diseases like Alzheimer's or Parkinson's physically change the brain. A doctor can look at a brain and say what the patient suffered from.
DAN GESCHWIND: It's not really possible with the psychiatric disorders.
KENNEDY: That's Dan Geschwind, a professor of neurogenetics at UCLA. He says researchers can't tell if a patient had schizophrenia or bipolar by looking at a brain or even a piece of tissue under a microscope. That's why psychiatric disorders are diagnosed by how the patient behaves. But recent advances in genetics have allowed the scientists to pinpoint the patterns of gene expression in the brain that are linked to these disorders. They measured RNA in 700 tissue samples from the brains of people with autism, schizophrenia, bipolar, major depression and alcoholism. RNA can show which genes are turned on and off and the tissue. The findings were published in Science.
GESCHWIND: With these new genomic molecular measurements, we're actually able to understand what is shared and what is distinct.
KENNEDY: The researchers found that the way genes express themselves in patients with autism, schizophrenia, and bipolar have a lot in common - fewer genes involved in signalling between neurons, and more genes related to neuroinflammatory cells. Major depression was very distinct, he says.
GESCHWIND: And alcoholism didn't overlap with any of them at all.
KENNEDY: Geschwind says that understanding the molecular signature of these disorders could help with curing them someday.
GESCHWIND: And so it gives us hope that perhaps we can use these signatures or hallmarks of the disorder to screen for drugs that would reverse them. Then we can test whether those drugs actually work on the symptoms in patients.
KENNEDY: He says that monkeys treated with an antipsychotic medication actually showed signs of reversing the genetic changes linked to autism and schizophrenia. The causes of these disorders are complicated, involving many different genes and other triggers, like the patient's life experiences. Geschwind says that's part of the reason why this research is so surprising, that they appear to have very different causes and yet display similar patterns when you look at it on a molecular level in the brain.
GESCHWIND: We think that having these patterns is the first step.
KENNEDY: A big question is understanding exactly what caused those changes. But Geschwind is hopeful that knowing the molecular basis of these disorders can help develop better treatments.
Merrit Kennedy, NPR News.
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