Gene Hunters Link Genes to Brain Size

Four New Papers May Pave the Way Toward New Treatments for Brain Diseases

By Denise Mann
WebMD Health News

Reviewed by Laura J. Martin, MD

April 16, 2012 -- An international team of gene hunters has zeroed in on genes that may play a role in boosting brain size and IQ.

The findings -- four studies in total -- appear online in Nature Genetics.

The implications of the new studies are much wider than whether or not you will attend an Ivy League school or become a member of Mensa, the high-IQ society. Researchers hope that, if validated by other studies, these genes may become targets for drugs that treat brain diseases such as Alzheimer's disease, depression, and other forms of mental illness.

More than 200 scientists from 100 institutions across the globe looked at brain scans and mapped genetic material or DNA from thousands of people. They turned up "extraordinary evidence," says Paul Thompson, PhD. He is one of the gene hunters on the team. Thompson is also a professor of neurology at the David Geffen School of Medicine at the University of California, Los Angeles, and a member of the UCLA Laboratory of Neuro Imaging.

Genes Are Not Destiny

The newly identified genes may affect our brain's vulnerability or resistance to brain diseases.

Genes are not destiny, Thompson says. "We can more than erase the effects of this bad gene by eating a healthy diet, exercising, and education," he says. Heart-healthy foods are known to be good for the brain as well.

All said, "the gene is one of any army of culprits we can to attack by developing new drugs."

So how far off are these drugs? "We are about five to 10 years away from developing targeted therapy which interferes with brain-aging genes," he says.

Many Genes Affect Intelligence

Richard J. Haier, PhD, reviewed the papers for WebMD. He is a professor emeritus at the University of California, Irvine, School of Medicine. "For the last 20 years, research in intelligence has become more and more focused on the [inner workings of the] brain."

In the past, intelligence was assessed via IQ tests using paper and pencils. Now, "there has been an explosive growth in the use of imaging technologies to study intelligence," Haier tells WebMD.

There are hundreds of genes that affect intelligence. "Each one contributes a little bit," he says.

The new information does not mean the genetic basis of intelligence has been discovered, but it does take us one step closer to decoding the IQ genes, he says.

The real victory will be if scientists can understand how these genes work. "Then you have a chance to develop ways to tweak those mechanisms," he says. For example, "if we can tweak this gene, we may be able to increase intelligence."

Brain growth primarily occurs during childhood and is linked to IQ. "We would have to intervene at a young age to have any effect on intelligence," Haier says.

The findings may also pave to way toward better treatments for brain disorders. "The hope is that we will be able to reverse or cure them by targeting genes," he says.

Sam Gandy, MD, PhD, is the Mount Sinai chair in Alzheimer's disease research at Mount Sinai School of Medicine in New York City. "Every new gene, whether good or bad, represents a new drug target," he tells WebMD via email. "The more targets we have, the better our chances of developing meaningful interventions."

According to Gandy, the new findings have no immediate implications for clinical medicine. That said, "these genes are signposts that keep us on the right track."


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SOURCES: Paul Thompson, PhD, professor of neurology, David Geffen School of Medicine at UCLA; member of the UCLA Laboratory of Neuron Imaging, Los Angeles. Sam Gandy, MD, PhD, Mount Sinai chair, Alzheimer's disease research, Mount Sinai School of Medicine, New York City. Richard J. Haier, PhD, professor emeritus, University of California at Irvine School of Medicine. Taal, RH. Nature Genetics, published online April 15, 2012. Stein, JL. Nature Genetics, published online April 15, 2012. Ikram, MA. Nature Genetics, published online April 15, 2012. Bis, JC. Nature Genetics, published online April 15, 2012.

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