Eamonn Sheridan - Finding disease genes

Kat - So what kinds of disease-causing genetic changes have turned up in the Born in Bradford study so far? One man who's been digging into the data is Eamonn Sheridan from Leeds University.

Eamonn - Well, from a straightforward academic perspective, we've identified 30 or 40 novel disease genes in that period of time at least. And several of those are tremendously interesting biologically. Usually, we only identify disease genes that cause disease in a couple of families locally. But the reason that it's important is because of what it tells us about basic biology. So, we've identified disease genes that are involved very basic mechanisms about the way that your brain grows and the way that your brain is formed, which is an extremely hot topic in biology generally. And then we've also identified genes that are involved in the way that the little energy factories in the cells, the mitochondria, the way that those work - fairly fundamental things about those. So, although we tend to identify disease genes which are of importance clinically to any restricted number of families, they're biologically really important because they give you shortcuts into understanding the biology which would otherwise be really difficult to obtain.

Kat - The Born in Bradford study is carrying on for a long time into the future. Do you think that the gene variations you've identified now are pretty much the low-hanging fruits? Do you hope that there's going to be many more coming out?

Eamonn - These are definitely the low-hanging fruit at the moment because these are the genes where faults in a single gene cause a single disorder, and that's relatively straightforward. But the nature of the Born in Bradford cohort particularly this kind of bi-ethnic mix of white British people and Pakistani people means that we can investigate other problems as well. One of the areas that we're particularly interested in is diabetes and we know that the frequency of diabetes in the Pakistani community is greater than the white British community. The comparison of genetic variation in those two communities ought to give us an idea of why it's more common in the Pakistani community than the white British community. Well, that's a longer term and much more complicated programme than we've pursued up to now.

Kat - More broadly speaking, how valuable to genetic researchers like yourself are these large cohort studies?

Eamonn - From the perspective of sorting out common diseases, there's absolutely no doubt that these large cohorts are the only way forward because in essence, with classical genetics where a fault in a single gene results in a single disorder, the effect of the variant is extremely high. It results in a distinct disorder. Whereas with common disorders, the effect of individual variation is going to be actually very small. And it's only by having large cohorts with big, big numbers, you can actually identify things that are likely to be significant.

Kat - Leeds University's Eamonn Sheridan.