Scientists Identify Genes Linked to Migraines

SUNDAY, June 12 (HealthDay News) -- Researchers have identified three genes linked to migraine headache and found that people who inherit any one of these genes have a 10 to 15 percent greater risk for the condition.

Migraine headache -- an abnormality in the response of nerve cells to stimuli -- is characterized by recurring severe headaches, which often result in nausea as well as sensitivity to light and sound.

In examining genetic data from more than 23,000 women, including over 5,000 migraine sufferers, the researchers found an association between the headaches and variations in three genes: TRPM8 (which plays a role in sensitivity to cold and pain), LRP1 (a gene involved in the transmission of signals between neurons) and PRDM16.

"While migraine remains incompletely understood and its underlying causes difficult to pin down, identifying these three genetic variants helps shed light on the biological roots for this common and debilitating condition," the study's lead author, Dr. Daniel Chasman, assistant professor in the preventive medicine division at Brigham and Women's Hospital and Harvard Medical School, said in a hospital news release.

One migraine expert called the findings "very exciting."

"The thinking for a long time was that migraine is most commonly a multi-genetic condition with potentially many genetic variations that contribute," noted Dr. Audrey Halpern, clinical assistant professor in the department of neurology at NYU Langone Medical Center in New York City. "We clearly understand now that migraine is a condition characterized by disordered sensory processing."

Although the study authors said the findings are encouraging, they noted that more research is needed to better understand exactly how each of these three genes is associated with migraine.

Halpern agreed that much more study lies ahead to unravel the genetics of migraine.

"This current research will help us more fully understand what happens during migraine, but there is also much more to learn," she said. "We've always known it's a genetic condition -- but the last 10 years we've learned it's a neurological condition. This study brings those two ideas together."

The report is published in the June 12 online edition of the journal Nature Genetics.

More information

The U.S. National Library of Medicine has more about migraines.

SOURCES: Audrey Halpern, M.D., clinical assistant professor, department of neurology, NYU Langone Medical Center, New York City; Brigham and Women's Hospital, news release, June 12, 2011Copyright

Scientists Find Molecular Similarities in Brains of Those With Autism

WEDNESDAY, May 25 (HealthDay News) -- The symptoms and severity of autism vary widely, but new research shows remarkable similarities at the molecular level in the brains of people with the disorder.

Researchers from Los Angeles, Toronto and London analyzed post-mortem brain tissue samples from 19 people with autism and 17 without.

In the healthy brains, researchers saw distinct differences in the gene expression in the frontal lobe vs. the temporal lobe of the cerebral cortex -- differences that help determine the structure and function of the two brain regions.

Specifically, between the frontal and temporal lobes in the healthy brains, more than 500 genes were expressed at different levels. Gene expression is the process by which a gene's DNA sequence is copied into RNA to produce proteins, which perform specific tasks within the cell.

But researchers didn't find those same patterns in autistic brains. Instead, researchers found only eight differences in the gene expression in the frontal and temporal lobes.

"In a healthy brain, the frontal and temporal lobes can be differentiated," said principal investigator Dr. Daniel Geschwind, a distinguished professor of neurology, psychiatry and human genetics at the David Geffen School of Medicine at UCLA. "But in autism we didn't see that. Instead, the frontal lobe closely resembles the temporal lobe."

Many of those regional differences in the cerebral cortex are established during fetal development, researchers added.

The study is published in the May 25 online issue of Nature.

Over the past decade, researchers have discovered lots of gene variants that seem to play a role in some cases of autism, but none of the mutations were present in a large percentage of people with the disorder.

Prior research has also implicated regions of the cerebral cortex, which is highly developed in humans, in autism. The frontal lobe is involved with judgment, language, planning, social cognition and personality, while the temporal lobe is important for language and emotions, Geschwind said.

But this is the first study to show differences in the patterns of gene expression between brain regions. It's those patterns of gene expression that enable the brain to function normally and to communicate properly with other regions of the brain, explained Robert Ring, vice president for translational research for Autism Speaks.

"This study allows us to look at the complexity of what's going on at a molecular level in the brain, a step up from the gene," Ring said. "Here we have the opportunity to really see that the development of normal brain physiology requires differences in the regional activity of gene networks. This report provides evidence that the expected pattern of these differences is absent in autism."

Researchers say the findings may help in the development of medications that target the pathways. "The fact that it's shared says there is some hope of beginning to unwind this and develop some treatments that would target those pathways," Geschwind said.

Compared to the healthy brains, autistic brains had less activity in the genes responsible for neuron function and communication, and a heightened level of gene expression in genes involved in immune function and inflammatory response.

Some of those genes have also previously been implicated in autism, researchers noted.

An estimated one in 110 U.S. children -- including one in 70 boys -- has an autism spectrum disorder, according to background information in the study. Autism affects behavior and impairs the ability to communicate and establish social relationships. Diagnoses have increased tenfold in the past decade.

More information

The U.S. National Institutes of Health has more on autism.

SOURCES: Daniel Geschwind, M.D., Ph.D., distinguished professor, neurology, psychology and human genetics, University of California, Los Angeles; Robert Ring, Ph.D., vice president, translational research, Autism Speaks, New York City; May 25, 2011, online, NatureCopyright