Note: Where available, the PDF/Word icon below is provided to view the complete and fully formatted document
Disclaimer: The Parliamentary Library does not warrant or accept liability for the accuracy or usefulness of the transcripts. These are copied directly from the broadcaster's website.
Variant linked to Alzheimer's may make you sm -

View in ParlViewView other Segments

ELEANOR HALL: The discovery that you have a genetic predisposition to Alzheimer's disease could
hardly be regarded as positive news.

But now a United States based neuropsychologist has found that the genetic variant linked to
Alzheimer's can also improve the brain function of carriers when they are younger.

The research results have surprised specialists both here and overseas as Sarah Dingle reports.

SARAH DINGLE: Assistant professor Duke Han from Rush University has been researching Alzheimer's
disease for years but even for him these results were unexpected.

DUKE HAN: I thought I actually made some sort of major mistake so I went back and did the analysis
over and over again, just because I was sure that it should been the opposite.

SARAH DINGLE: Professor Han's work examined epsilon 4, a variant of a particular gene known as
apolipoprotein E or APOE. The epsilon 4 variant is the best established genetic risk factor for
Alzheimer's disease.

DUKE HAN: We looked at young people in the military who sustained a mild to moderate head injury
and we predicted that people who had this APOE, epsilon 4 allele would do worse after a head injury
just because it seems to be associated with Alzheimer's disease and at least in older people it
seems to be associated with worse outcomes after head injury.

However when we did the analysis we actually found the opposite. That people who had this
particular genetic trait actually fared better at least from a cognitive standpoint. The one
difference being that this population that we looked at was actually fairly younger.

SARAH DINGLE: He says other papers have found young students with the epsilon 4 variant tend to be
associated with better school marks and had some superior memory results.

Professor Han says to explain this, he turned to evolutionary biology.

DUKE HAN: Came across this concept of antagonistic pleiotropy - that certain genes can actually
have opposite affects across the lifespan. That they can convey a benefit earlier in life and then
convey some sort of risk in later in life and that is why it is still represented in our gene pool
if you will.

LYNETTE MOORE: Well it's a real irony that the gene variant which seems to cause a greater risk of
dementia in older age actually may help younger people, that same gene.

SARAH DINGLE: Lynette Moore is from Alzheimer's Australia.

LYNETTE MOORE: That is an interesting piece of research that we'll have to watch for further
studies. It does, as I say, seem a little at odds with that theory that if you work your brain
harder you build up more of those brain connections and that gives you a bit of protection because
of that brain reserve you carry into older age.

SARAH DINGLE: She says it doesn't change the message that keeping your brain active may help reduce
the risk of Alzheimer's disease.

LYNETTE MOORE: The relationship between these risk genes and lifestyle, that is a critical area for
research. We need a whole range of research to try to get the answers to the risk associated with
Alzheimer's and the cure.

SARAH DINGLE: Professor Han says epsilon 4 could be a good place to start.

DUKE HAN: If we can come to an understanding of how that happens then theoretically we might be
able to actually affect that process later in life, whether it be the delay of the downside of
possessing that trait or the increase of the good side and just translating that to older age.

SARAH DINGLE: He says seeing epsilon 4 as a beneficial genetic trait instead of a cause for concern
could make a crucial difference.

ELEANOR HALL: Sarah Dingle reporting.