Rapid genome sequencing could revolutionize infant epilepsy diagnosis
A new study has found that rapid genome sequencing is a fast and effective way to diagnose infant epilepsy, a condition that, if left untreated, can lead to developmental delays. The researchers hope that their findings mean this cutting-edge technology will become more widely available.
Unlike the familiar jerking seizures seen in adult epileptics, infantile epilepsy usually manifests as subtle focal seizures and spasms, such as brief back stiffness or upward eye movement. Prolonged untreated seizures can be dangerous and can interfere with the child’s growth and development, so it’s important that the condition is diagnosed and treated early.
Infantile epilepsy is often caused by genetics. There are more than 800 known different genetic causes of infantile epilepsy currently, and many have similar symptoms. Rapid genome sequencing (rGS) is a fast way of testing for changes in DNA that could cause or contribute to a medical condition. An international study led by the Murdoch Children’s Research Institute is the first to examine rGS as a way of quickly diagnosing new-onset epilepsy in babies.
“Uncontrolled seizures in a baby’s developing brain can lead to high rates of developmental setbacks,” said Katherine Howell, one of the study’s co-authors. “Identifying the cause early can help guide treatment options, such as medication changes, which can improve seizure control. However, current genetic testing methods often take months or even years, resulting in missed opportunities.”
Here, Howell is referring to so-called rapid genetic testing, which can look at all the genes in the DNA (whole exome) or just the genes related to a medical condition (clinical exome). It’s different to rGS, which looks at all of a person’s DNA, not just the genes.
The researchers recruited 100 infants from Australia, Canada, London, and the US with new-onset epilepsy. Blood samples were taken from the infants and, where possible, one or both biological parents. After analyzing the samples, they found that rGS had a high diagnostic rate of 43% for infantile epilepsy. As a result of diagnosis using rGS, 56% of babies in the study had their treatment plans changed.
In some cases, genetic diagnosis suggested a relatively good prognosis, with a high likelihood of weaning antiseizure medication and normal development. In other cases, it suggested a relatively poor prognosis, with a high likelihood of drug-resistant seizures, developmental delay or intellectual disability, and even early death. In both circumstances, this information was valuable for formulating a plan of patient care.
Additionally, the researchers found that ‘trio’ rGS – analyzing samples from both parents and the child – can identify secondary or incidental diagnostic findings in the infant and the parents, as was seen in 5% of study participants.
The findings, say the researchers, point to the need for greater access to cutting-edge technology like rGS to improve patient treatment.
“We expect rapid genome sequencing to improve the outcome of babies with epilepsy by providing individualized care, tailored to the underlying cause, at the earliest possible stage,” Howell said. “More than half who received a diagnosis in our study saw their treatment change, a remarkable outcome for this vulnerable population.”
Longitudinal follow-up studies will be needed to demonstrate the importance of rapid diagnosis in improving clinical, quality of life and economic outcomes for patients.
The study was published in the journal The Lancet Neurology.