[ASC-media] One unlucky letter causes an infant epilepsy
niall at scienceinpublic.com.au
Sun Jan 15 01:54:55 CET 2012
A 20 year old mystery was solved this week with the discovery that an epilepsy that affects infants is caused by the change of a single letter in one gene. Seizures in infancy are not rare, but this familial epilepsy occurs in probably 60 families across Australia. It can also cause a movement disorder later in life.
The discovery was made by teams from the University of South Australia led by Associate Professor Leanne Dibbens and the Florey Institutes/University of Melbourne led by Professor Ingrid Scheffer. She is the 2012 Asia-Pacific L'Oréal-UNESCO For Women in Science Laureate and will receive her award in Paris in March.
Prof Scheffer first started looking at benign familial infantile epilepsy some twenty years ago. "I have now met many families where several members had seizures beginning at around 6 months and the inheritance pattern looked like it was due to a single gene. Sometimes the baby's parents had a movement disorder that often had not been diagnosed. " she says.
"Fortunately, while this form of epilepsy can be terrifying for both infant and parents it is self-limiting. Children grow out of it and it doesn't affect their intelligence. However it can reappear in later childhood or adolescence as a movement disorder. When you try to move a limb, it has a 'mind of its own' and moves in an odd direction. For one of my patients this often happens when the light changes at a pedestrian crossing and he goes to cross the road."
"Another of my patients is a dancer. Just before she starts to dance she has learnt to prepare her body by making a first movement then waiting for a moment for the abnormal movement and sensation to pass."
Prof Scheffer and colleagues have been keen to identify the cause of the condition.
15 years ago the mutation was pinned down to chromosome 16 but neither they, nor many other researchers worldwide could identify the gene until last year.
A Chinese team looking at a movement disorder found that it was due to a mutation which adds just one more code (C) to a twelve code sequence on chromosome 16 affecting a gene called PRRT2. Their publication (Chen et al, Nature Genetics 2011) gave Scheffer and her colleagues the clue they needed.
"We went straight to the families we know with the condition," she says. "We found a mutation in the PRRT2 gene in 19 of the 23 families, and 15 had the exact same mutation with the extra C despite being of many different nationalities. This suggests it is a mutation 'hotspot'."
"Now we've identified the mutation we can screen infants and predict the risk of seizures. We know that this gene makes a protein called proline rich transmembrane protein 2. That means we can hone in on what's happening biochemically and start to develop targeted treatments for the condition."
The research was published on Friday, 13 January 2012 in the American Journal of Human Genetics.
Ingrid is one of five L'Oréal-UNESCO For Women in Science Laureate for 2012. Each will receive US$100,000 in recognition of her contribution to the advancement of science at the Awards Ceremony on 22 March 2012 at the UNESCO Headquarters in Paris.
For L'Oréal Australia, Niall Byrne, niall at scienceinpublic.com.au<mailto:niall at scienceinpublic.com.au>, 0417 131 977
For the University of South Australia:
§ Sarah Heron (first author), 08 8302 2737, Sarah.Heron at UniSA.edu.au<file:///C:\Users\Niall\AppData\Local\Microsoft\Windows\Temporary%20Internet%20Files\Content.Outlook\INSAVF30\Sarah.Heron@UniSA.edu.au>;
§ Leanne Dibbens (project leader), 08 8302 1124, Leanne.Dibbens at UniSA.edu.au<file:///C:\Users\Niall\AppData\Local\Microsoft\Windows\Temporary%20Internet%20Files\Content.Outlook\INSAVF30\Leanne.Dibbens@UniSA.edu.au>;
§ Kelly Stone, UniSA media 08 8302 0963, Kelly.Stone at unisa.edu.au<file:///C:\Users\Niall\AppData\Local\Microsoft\Windows\Temporary%20Internet%20Files\Content.Outlook\INSAVF30\Kelly.Stone@unisa.edu.au>.
For the Florey Institutes/University of Melbourne:
§ Prof Ingrid Scheffer (project leader), 03 9035 7344, scheffer at unimelb.edu.au<mailto:scheffer at unimelb.edu.au>
§ Amanda Place, Florey PR, 0411 204 526, aplace at unimelb.edu.au<mailto:aplace at unimelb.edu.au>
§ Annie Rahilly, University of Melbourne media office, 0432 758 734, arahilly at unimelb.edu.au
About Professor Ingrid Scheffer:
About Associate Professor Leanne Dibbens
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niall at scienceinpublic.com.au<mailto:niall at scienceinpublic.com.au>
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