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As early as 3 months of age, infants with a severe form of epilepsy called Dravet syndrome start having convulsive seizures, during which their arms and legs jerk repeatedly. As they become toddlers, another type of seizure begins to appear.
These seizures do not cause obvious convulsions, but disrupt consciousness and can occur more than 50 times every single day. A challenge to detect and difficult to treat, these non-convulsive seizures often go unnoticed by parents and physicians.recent study, published in the journal Cell Reports, characterizes these silent seizures in a mouse model of Dravet syndrome and identifies the brain area that could be targeted to stop them.
“We were able to pinpoint the exact spot in the brain that causes the seizures,” said Jeanne Paz, Ph.D., the senior author of the study, who is an assistant investigator at the Gladstone Institutes. “This discovery allowed us to develop two new strategies to prevent these non-convulsive seizures in mice simulating Dravet syndrome.”
By collaborating with Maria Roberta Cilio, MD, Ph.D., a renowned pediatric epileptologist at UC San Francisco, Paz confirmed that her findings are likely relevant to the human condition.
“If we could successfully eliminate non-convulsive seizures in children with Dravet syndrome, we could significantly improve their quality of life,” said Cilio, director of research at the UCSF Pediatric Epilepsy Center. “We could finally offer them the best conditions in which to reach their full potential.”
“If we could successfully eliminate non-convulsive seizures in children with Dravet syndrome, we could significantly improve their quality of life,” said Cilio, director of research at the UCSF Pediatric Epilepsy Center. “We could finally offer them the best conditions in which to reach their full potential.”
Nearly 8 in 10 patients with Dravet syndrome have a genetic mutation that causes both developmental delays and seizures, which can even lead to sudden death. Affected children also have cognitive deficits, sleeping difficulties and autism-like behaviors.
Neurons are highly specialized brain cells that send signals to one another, forming complex network that enable both basic and higher brain functions. When a neuron “fires,” it releases a signal that carries instructions for the receiving cell. While excitatory cells instruct the next cell to take action, inhibitory cells send signals to suppress the activity of receiving cells.
Seizures are caused when excitatory cells function too strongly or inhibitory cells function too weakly both of which result in too many cells in the brain getting excited at the same time.
Previous animal studies had shown that convulsive seizures are caused when inhibitory cells are not sufficiently active in a brain region called the cerebral cortex. Since then, the scientific field has focused on finding treatments to enhance the function of those cells.