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A group of seizure disorders called epileptic encephalopathies, affect the developing brains of babies and children. They are devastating disorders as, in addition to causing severe disruptive seizures, they lead to retarded development in terms of intellectual ability and behaviour, and sometimes to death. It is thought that the seizures damage the child’s developing brain, affecting development.
New research, published this year has made discoveries that might make it easier to diagnose and design targeted treatments for these particular disorders.
What are epileptic encephalopathies?
There are over 40 different types of epilepsy and the one which featured in the new research is a particularly devastating one. It is thought that the development of the child’s brain is the trigger for the seizures seen in this type of epilepsy, which means that the characteristics of the seizures change as the child becomes older and the brain matures. In fact the seizures usually stop in adolescence.
What was ground-breaking about this research?
A research team at University of Melbourne and the Florey Institute of Neuroscience and Mental Health, headed up by Professor Ingrid Scheffer, worked out some of the genes responsible for causing this terrible illness. They analyzed genetic material from 500 children with the disorder, using state-of-the-art techniques. These enabled them to target genes known, or suspected of being the faulty ones, which cause the condition. Previously they would have had to look through thousands of genes in a very labor-intensive and inefficient way.
What did they discover?
Of the 65 genes they analyzed from the cases of epileptic encephalopathy, 19 were known to be associated with the disorder and the other 46 were suspected of it.
In more than 10% of the cases they found that the suspect genes had mutated, leading to development of the condition. A mutation is a spontaneous change in a gene, meaning it does not function in the way that it should, leading to development of a disorder.
To use a more widely-known example, the BRCA genes associated with breast cancer normally prevent cancer by repairing damaged DNA. It is only when they become faulty through a mutation that breast cancer can develop.
Two new genes, called CHD2 and SYNGAP1, which had not previously been known about, were found to be associated with development of this particular epileptic disorder.