Anti-seizure drugs don’t work in about a third of people with epilepsy. But for people with focal epilepsy, whose seizures originate in a discrete area of the brain, surgery is sometimes an option. The diseased brain tissue that’s removed also offers a rare opportunity to discover epilepsy-related genes.
Many mutations causing epilepsy have been discovered by testing DNA taken from the blood. But it’s becoming clear that not all epilepsy mutations show up on blood tests. So-called somatic mutations can arise directly in tissues like the brain during early prenatal development. Even within the brain, these mutations may affect only a fraction of the cells — those descended from the original mutated cell. This can create a “mosaic” pattern, with affected and unaffected cells sometimes intermingling.
One of the first such mutations to be described, by Ann Poduri, MD, MPH, and colleagues at Boston Children’s Hospital in 2012, was in Dante, a young boy who was having relentless daily seizures. The entire right side of Dante’s brain was malformed and enlarged, and he underwent a drastic operation, hemispherectomy, to remove it. Only later, studying brain samples from Dante and similar children, did Poduri find the genetic cause: a mutation in the gene AKT3. It affected only about a third of Dante’s brain cells. …
Head shaved, a little boy rests on the operating table, deep under anesthesia. His parents have brought him to Boston Children’s Hospital in hopes of determining the cause of his seizures. Now, neurosurgeons Scellig Stone, MD, PhD, Joseph Madsen, MD, and their colleagues in the Epilepsy Center are performing a procedure designed to monitor seizure activity in the 3-year-old’s brain.
But as the team members crowd around the table, they’re not alone. With the push of a button, a large robotic arm rotates and lowers right next to the boy’s head, helping the physicians pinpoint the precise location to drill. “This is a real game-changer,” murmurs one of the clinicians observing the surgery. “It’s going to transform the way we practice.” …
In the U.S., about one in 100 people have some form of epilepsy. A third of those people have seizures that cannot be controlled with drugs, eventually requiring surgery to remove the area of their brain tissue that is triggering seizure activity.
“If you can identify and surgically remove the entire epileptogenic zone, you will have a patient who is seizure-free,” says Christos Papadelis, PhD, who leads the Boston Children’s Brain Dynamics Laboratory in the Division of Newborn Medicine and is an assistant professor in pediatrics at Harvard Medical School.
Even experts in this field were skeptical for years about the non-invasive detection of HFOs. But now, thanks to our study and other researchers’ work, these people are changing their minds. At present, however, these surgeries are not always successful. Current diagnostics lack the ability to determine precisely which parts of an individual’s brain are inducing his or her seizures, called the epileptogenic zone. In addition, robust biomarkers for the epileptogenic zone have been poorly established.
But now, a team at Boston Children’s Hospital is doing research to improve pre-surgical pinpointing of the brain’s epileptogenic zone. They are using a newly-established biomarker for epilepsy — fast brain waves called high-frequency oscillations (HFOs) — that can be detected non-invasively using scalp electroencephalography (EEG) and magnetoencephalography (MEG). …
When epilepsy can’t be controlled with drugs, neurosurgery is sometimes curative, if the seizures are coming from discrete brain tissue that can be safely removed.
Finding these diseased areas, however, can require invasive surgery to place grids of electrodes on the brain’s surface. That’s followed by long-term, 24-hour EEG monitoring — typically for a week — until a seizure happens. Neurosurgeons then use this data to map a surgical path. But to actually remove the diseased tissue, a second operation is needed.
That’s enough to deter many families from epilepsy surgery. But what if seizure origins could be mapped without having to actually observe a seizure?
Joseph Madsen, MD, director of Epilepsy Surgery at Boston Children’s Hospital, and Eun-Hyoung Park, PhD, a computational biophysicist in the Department of Neurosurgery, think they have a way to do that — with an algorithm originally used for economic forecasting. …
A person born with a port-wine birthmark on his or her face and eyelid(s) has an 8 to 15 percent chance of being diagnosed with Sturge-Weber syndrome. The rare disorder causes malformations in certain regions of the body’s capillaries (small blood vessels). Port-wine birthmarks appear on areas of the face affected by these capillary malformations.
Aside from the visible symptoms of Sturge-Weber, there are also some more subtle and worrisome ones. Sturge-Weber syndrome can be detected by magnetic resonance imaging (MRI). Such images can reveal a telltale series of malformed capillaries in regions of the brain. Brain capillary malformations can have potentially devastating neurological consequences, including epileptic seizures.
Frustratingly, since doctors first described Sturge-Weber syndrome over 100 years ago, the relationship between brain capillary malformations and seizures has remained somewhat unexplained. In 2013, a Johns Hopkins University team found a GNAQ R183Q gene mutation in about 90 percent of sampled Sturge-Weber patients. However, the mutation’s effect on particular cells and its relationship to seizures still remained unknown.
But recently, some new light has been shed on the mystery. At Boston Children’s Hospital, Sturge-Weber patients donated their brain tissue to research after it was removed during a drastic surgery to treat severe epilepsy. An analysis of their tissue, funded by Boston Children’s Translational Neuroscience Center (TNC), has revealed the cellular location of the Sturge-Weber mutation. The discovery brings new hope of finding ways to improve the lives of those with the disorder. …
A quick look at recent research Vector finds noteworthy.
Tracking infants’ microbiomes
Microbiome studies are blooming as rapidly as bacteria in an immunocompromised host. But few studies have been done in children, whose microbiomes are actively forming and vulnerable to outside influences. Two studies in Science Translational Medicine on June 15 tracked infants’ gut microbiomes prospectively over time. The first, led by researchers at the Broad Institute and Massachusetts General Hospital, analyzed DNA from monthly stool samples from 39 Finnish infants, starting at 2 months of age. Over the next three years, 20 of the children received at least one course of antibiotics. Those who were repeatedly dosed had fewer “good” bacteria, including microbes important in training the immune system. Overall, their microbiomes were less diverse and less stable, and their gut microbes had more antibiotic resistance genes, some of which lingered even after antibiotic treatment. Delivery mode (cesarean vs. vaginal) also affected microbial diversity. A second study at NYU Langone Medical Center tracked 43 U.S. infants for two years and similarly found disturbances in microbiome development associated with antibiotic treatment, delivery by cesarean section and formula feeding versus breastfeeding. …
An occasional roundup of news items Vector finds interesting.
Blood-brain barrier on chip
The blood-brain barrier protects the brain against potentially damaging molecules, but its gate-keeping can also prevent helpful drugs from getting into the central nervous system. Reporting in PLoS One, a team at the Wyss Institute for Biologically Inspired Engineering describes a 3-D blood-brain barrier on a chip — a hollow blood vessel lined with living human endothelial cells and surrounded by a collagen matrix bearing human pericytes and astrocytes. …
Nine-year-old Haley Hilt has had intractable seizures all her life. Though she cannot speak, she communicates volumes with her eyes. Using a tablet she controls with her gaze, she can tell her parents when her head hurts and has shown that she knows her letters, numbers and shapes.
Haley is one of a growing group of children who are advancing the science around CDKL5 epilepsy, Haley’s newly recognized genetic disorder. When Boston Children’s Hospital geneticist Joan Stoler, MD, diagnosed Haley in 2009, there were perhaps 100 cases known in the world; today, there are estimated to be a few thousand. Haley’s neurologist, Heather Olson, MD, leads a CDKL5 Center of Excellence at the hospital that is bringing the condition into better view. …
Since we spoke with the founders of TriVox Health in 2014, their disease management program has taken off. The program began in Boston Children’s Hospital’s Division of Developmental Medicine as a way to more efficiently collect information on children’s ADHD symptoms from parents and teachers. It is now a user-friendly, web-based platform for tracking multiple conditions, incorporating medication confirmation, side effects reporting, disease symptom surveys and quality of life measures.
Epileptologist Tobias Loddenkemper, MD, director of clinical epilepsy research at Boston Children’s Hospital, is a seizure whisperer. He keeps a close watch on his patients, trying to discern seizure patterns and head off the developmental and learning problems that seizures can cause. A pioneer in the emerging field of chronoepileptology, he has partnered with Empatica and other companies to develop reliable seizure detection devices that could help doctors better time medication dosing and help prevent death from seizures, a real risk in children with severe epilepsy.