Hi, it's Ira Flato, and this is Science Friday. Today on the podcast, trying to untangle the

genetic factors involved in Alzheimer's disease. Although the exact mechanism of the illness is still

a mystery, researchers hope work like this could point to new areas to study and maybe potential treatments.

Joining me now is Dr. Dylan Williams, his principal research fellow in molecular and genetic epidemiology

at University College London in the UK. Welcome to Science Friday. Thank you very much. It's pleasure to be

speaking to you. Thank you. You're It's a pleasure to be speaking to you.

Thank you. You're looking at variations, if I understand it, in one specific gene called APOE.

What does that gene do normally? Why are you looking at that? So, as background, this protein apollipar protein E, or APOE for short, is a small protein which has a well-established role

in shudlinic fat around the body. And we also know it has diverse roles in the brain.

People can inherit one of three types of the gene, which we refer to as E2, E3, and E4. And so we've known for about 30 years that the risk of Alzheimer's disease

differs between people depending on which type of apoid gene they inherit. E2 is low risk,

E3 is medium risk, and E4 is high risk. And this gradient of risk is common knowledge amongst Alzheimer's disease

researchers. However, knowledge of this gradient alone doesn't tell us that always full importance.

And to grasp that, I think we need to answer what is, a face value, a fairly simple question.

So what proportion of Alzheimer's disease cases would not occur

without the impact of the medium and the high risk forms of the gene? In other words,

if we were to take away effects of E3 and E4, the medium and high risk versions of the gene from

people, with approaches such as gene therapy or other drugs,

how much Alzheimer's disease do we think we would prevent?

So you leave the other population of people with that other gene alone and just tackle the

medium or high risk factor?

That's right. So we're really interested in knowing what this one gene's contribution is.

...