Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene mutation causes severe epilepsy, febrile seizures in thousands of infants worldwide

21.09.2009
Sodium channel gene linked to Dravet syndrome

University of Utah medical researchers have identified a gene with mutations that cause febrile seizures and contribute to a severe form of epilepsy known as Dravet syndrome in some of the most vulnerable patients – infants 6 months and younger.

The discovery, published online in PLoS Genetics, means some infants with Dravet syndrome, a type of epilepsy that often begins with fever-induced (febrile) seizures, would benefit from genetic testing to identify whether they have a mutation in the SCN9A gene, which the researchers found causes seizures by affecting sodium channels in the brain. Infants who have the mutation might well be better off not receiving sodium channel blockers, some of the most common anticonvulsant drugs, because they could make a sodium channel-induced seizure worse, the researchers report.

The study was a collaboration of researchers from several departments in the U of U School of Medicine and College of Pharmacy, as well as national and international colleagues. First author Nanda A. Singh, Ph.D., a researcher in the University's Eccles Institute of Human Genetics, said the SCN9A mutation is the fifth gene discovered to cause febrile seizures and, before now, was not suspected in seizures or epilepsy.

"This new gene gives us a much needed novel target for developing more effective drugs to treat those children with debilitating seizures," Singh said.

Groundwork for the study was laid by two U of U School of Medicine physicians, Joel Thompson, M.D., and Francis M. Filloux, M.D., professor of pediatrics and neurology, who in the 1990s met a patient whose family had a history of the febrile seizures. After studying the DNA of 46 members of the extended family, researchers at the U of U identified an area on chromosome 2 as a likely place to find the gene mutation associated with the family's seizures. Using that data, they pinpointed the SCN9A mutation as the seizure-causing gene in the family.

To confirm SCN9A's role, the researchers used technology pioneered by the University of Utah's 2007 Nobel laureate in medicine, Mario R. Capecchi, Ph.D., to create mouse models with the gene mutation. The researchers tested the animals for seizures and found the mice with the SCN9A mutation had significantly lower thresholds for developing seizures than mice without the mutation.

"The mouse data confirmed that the SCN9A mutation is causing the febrile seizure disease in this family," Singh said. The researchers further showed the SCN9A seizure-causing role in approximately 5 percent of 92 unrelated febrile syndrome patients.

The SCN9A gene provides instructions for the body to make sodium channels, which act as conduits and gates to let sodium ions into cells and help conduct electricity for neurons to communicate. But when the gene mutates, it can cause seizures by altering sodium channel function in the brain and preventing neurons from firing properly. Mutations in four other genes had been shown in other studies to cause febrile seizures, and one sodium channel gene in particular, SCN1A, has been found in about half of patients with Dravet syndrome. In DNA collected by Belgium researchers, headed by Peter De Jonghe, Singh and her colleagues found additional SCN9A mutations in about 9 percent of Dravet syndrome patients, while 6 percent had both SCN9A and SCN1A gene mutations.

For infants and children who suffer febrile seizures or have Dravet syndrome, the study offers hope where there often is little to be found, according to Kris Hansen, president of the Epilepsy Association of Utah and mother to a child with Dravet syndrome. "Dravet is such a hard syndrome to control, and any research that gives us reasons for what is happening with our children and hope for the future is absolutely amazing," Hansen said. "This medical breakthrough will bring prospects of relief to families dealing with the ongoing challenges of Dravet syndrome and febrile seizures."

Febrile seizures are the most common form of early childhood seizures and strike up to 1 in 20 children in North America. Most infants outgrow them, but in some cases the seizures continue into adulthood. Epilepsy is a disorder of many types of seizures that affects nearly 3 million people in the United States, with approximately 200,000 new cases reported each year. Patients with Dravet syndrome can have febrile and other seizures severe enough to stunt mental and social development.

Because half of Dravet syndrome patients have SCN1A mutations, these patients are tested for that form of the disorder for the mutation. In those who don't have the SCN1A mutation, Singh suggests a second test could determine if they have the SCN9A mutation. In patients who have one or both of the genes, treatment could be modified to exclude sodium channel-blocking drugs.

The study was funded by the National Institutes of Health, Keck Foundation, and the Salt Lake City-based Ben B. and Iris M. Margolis Foundation.

This study was a collaboration of researchers from the University of Utah School of Medicine's Department of Human Genetics, divisions of Pediatric Neurology and Medical Genetics, and the College of Pharmacy's Anticonvulsant Drug Development Program. Researchers from the University of Washington and University of Antwerp, Belgium, also collaborated on the study. Mark F. Leppert, Ph.D., professor of human genetics in the University of Utah School of Medicine was the study's senior author.

Phil Sahm | EurekAlert!
Further information:
http://www.utah.edu

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>