In a new study, researchers found a new brain disorder in which children experience developmental regression and severe epilepsy.
They found a variation in a gene causes a severe childhood-onset neurodegenerative disorder that has never before been described.
This newly discovered condition was different from other chronic neuroinflammation implicated in other neurodegenerative conditions such as Alzheimer’s disease, Parkinson’s disease and frontotemporal dementia.
The research was led by the Murdoch Children’s Research Institute (MCRI) in Australia.
The study looked at six children from four families with the gene variant who had a similar degenerative condition, the cause of which was unlocked by genomic testing.
The study participants started with normal or mild developmental delay, and the onset of seizures started within the first year of life.
All had severe and progressive developmental regression following a seizure.
The team says the disorder, with features suggestive of neuroinflammation, appeared to require two copies of the defective gene, meaning both parents had to be carriers of one altered copy.
While the families do not report that their two families are directly related, they are presumed to be distantly related due to the overlap of their family histories, with common ancestors originating from the same town.
The researchers used advanced molecular techniques to dissect the likely cellular pathway affected by the mutation in the NRROS gene.
By inserting the gene into cells in the laboratory, they identified other molecules that NRROS interacts with.
These molecules are crucial for a number of brain cell functions, including adding the insulating layers around nerve fibers and producing brain immune cells.
In line with these laboratory findings, the study participants had neurodegenerative symptoms with difficult to control epilepsy, developmental regression, and delayed myelination.
The myelination process is vitally important to healthy central nervous system functioning, enabling nerve cells to transmit information faster and allows for more complex brain processes.
The outcomes of this research highlighted the power of new genomic sequencing technologies that had ended a diagnostic odyssey that for some families may take years.
One author of the study is Associate Professor Sue White.
The study is published in the American Journal of Human Genetics.
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