Friday July 19, 2019

Researchers Identify Gene Associated with Sudden Death in Epilepsy

The researchers observed the mice with Dravet syndrome had bad seizures that became more severe when the mice got hot, exactly like humans with Dravet syndrome

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Structure of brain can help find the causes behind epilepsy.
Structure of brain can help find the causes behind epilepsy.

Researchers have identified a gene associated with sudden death in epilepsy.

Usually, it is believed that the patient had a seizure that killed them. But seizures happen in the cortex, the top of the brain and life-sustaining processes like breathing are controlled somewhere else entirely — the brainstem, the very bottom part of the brain that connects to the spinal cord.

In a study, published in the scientific journal ‘eLife’, the researchers from the University of Connecticut tried to figure out if there was a genetic basis for sudden unexpected death in epilepsy (SUDEP). They tried to understand if the same genetic mutation that causes the seizures also disrupts the cells in the brainstem that control breathing.

For the study, researchers raised mice with the human mutation for a severe form of epilepsy called Dravet syndrome, which is caused by mutations in a gene that shapes the channels through which sodium moves in and out of cells in the brain. If the sodium channels don’t function properly, cells can get overexcited. One cell’s over-excitement can travel through the brain like hysteria through a crowded stadium, stampeding into a seizure.

The gene mutated in the Dravet syndrome is called the sodium channel gene 1a or ‘Scn1a’. It’s considered a super-culprit for epilepsy, with more than 1,200 different Scn1a mutations identified.

The severity of epilepsy caused by Scn1a depends on whether the mutation causes partial or complete loss of the sodium channel’s function.

People with Dravet syndrome tend to have dramatic seizures, exacerbated by hot weather and the syndrome is very hard to control with anti-epileptic medications.

Epilepsy drug in pregnant women may increase oral cleft risk in baby
Epilepsy drug in pregnant women may increase oral cleft risk in baby. Wikimedia Commons

The study’s findings showed that Scn1a mutation makes the sodium channels less active. Instead of making cells overactive, it makes them underactive.

This mutation mostly affects inhibitory cells or cells in charge of calming the brain down.

To understand how this might lead to the patients’ sudden death, the researchers tested whether the mice with the Dravet syndrome mutation show breathing problems and die prematurely of SUDEP and also, whether the cells in the part of the mice’s brainstem that controls breathing were normal or were somehow perturbed by the mutation.

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The researchers observed the mice with Dravet syndrome had bad seizures that became more severe when the mice got hot, exactly like humans with Dravet syndrome.

They also found that mice with Dravet Syndrome had a breathing disorder. They tended to hyperventilate (breathe too little) for no apparent reason sometimes. Other times they would have long apneas or pauses between breaths. And these mice didn’t breathe more in response to high carbon dioxide levels in the air, the way humans and normal mice do.

“We felt really good that our model was reflecting the human condition,” noted Dan Mulkey, a neuroscientist from the University of Connecticut. (IANS)

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WHO: Millions of People with Epilepsy Reluctant to Seek Treatment Because of Stigma

Nearly 50 million people around the world suffer from epilepsy

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epilepsy
Nearly 50 million people around the world suffer from epilepsy. The World Health Organization reports this neurological disease affects people of all ages in all walks of life. VOA

The World Health Organization says millions of people with epilepsy are reluctant to seek treatment because of the stigma attached to their ailment, leading to the premature death of many.  WHO has released the first global report on epilepsy.

Nearly 50 million people around the world suffer from epilepsy.  The World Health Organization reports this neurological disease affects people of all ages in all walks of life.  It says this brain disease can cause seizures and sometimes loss of awareness.

Program Manager in WHO’s Department of Mental Health and Substance Abuse, Tarun Dua says people with epilepsy suffer widespread stigma and discrimination as a consequence of their unusual behavior.

epilepsy
Low doses of topiramate may also increase the risk of oral clefts but to a lesser extent. Wikimedia Commons

“So, in many settings, people with epilepsy they are embarrassed…children are not allowed to go to school, adults are not allowed to work, sometimes not even marry or the right to drive is also not there,” said Dua. “So, these stigma and human rights violations and sometimes also the death that is associated with epilepsy—so premature mortality in epilepsy is three times that of the general population.”

Causes of epilepsy include injury around the time of birth, brain infections from illnesses such meningitis or encephalitis and stroke.  WHO estimates 25 percent of cases are preventable.

Dua says early death among people with epilepsy in low and middle-income countries is significantly higher than in wealthy countries.  She says the stigma associated with epilepsy is a main factor preventing people from seeking treatment.

epilepsy
The World Health Organization reports this neurological disease affects people of all ages in all walks of life. Wikimedia Commons

She says low cost, effective medication to treat the disease is largely unavailable in poor countries as are the number of specialists competent to deal with this brain disorder.

ALSO READ: Researchers Identify Gene Associated with Sudden Death in Epilepsy

“For example, if you look in low and middle-income countries, there is only one neurologist per one million population,” Dua said. “Now, that is definitely insufficient to provide care for all people with epilepsy.  What it means is that we need the non-specialists, the primary care doctors to take care for people with epilepsy.”

Dua says WHO has the tools and evidence-based guidelines that show epilepsy can be successfully treated in primary health care.  She says pilot programs introduced in Ghana, Mozambique, Myanmar, and Vietnam are making huge inroads in closing the epilepsy treatment gap. (VOA)