Professor Judith Rapoport discusses techniques for finding rare structural variants in the genome, which may cause many disorders including childhood schizophrenia.
It’s hard to get agreement (on rare structural variants). The problem isn’t that we aren’t there yet, it’s that no two people are using the exact same screening method or definition. So, the ones we reported in the Science paper were only 100 kilobases (kb) and larger, whereas the screening we are doing now with the million SNP chip can go down to much smaller than that – a few base pairs. As a result, depending on the wider your range is that you’re looking at, the more that you’ll find.
The ones that we have called rare are the ones that we couldn’t find in any normative database. But other people are using it if they just find one out of several thousand. So, there is so much information and no two people are using the same technique. But rare would be it was either never or very unlikely, and we will have to be dealing with this again because we are essentially redoing our copy number study with a much, much finer screen, both because we had some evidence that the very small ones not reported in the Science paper may be particularly frequent in our patients with childhood schizophrenia.