WHDC Lafora Screening Programme update
The WHDC has published this, today:
Since our last update, we have received additional communication from Dr Minassian and his team in Canada, confirming that the testing is continuing to prove very difficult. He explains the difficulty with the current method of testing (Polymerase Chain Reaction).
“All modern methods rely on PCR, which amplify the segment of the mutation to detect, in this case, the expanded abnormal copy. This is very difficult in this case because the expansion is a massive repeat of the same nucleotides (letters of the code), and these nucleotides are the G’s and C’s which when repeatedly expanded like this make PCR very difficult. We are therefore in each case having to use extensive control experiments and numerous repeats to get the result we trust. We can continue doing this, but things will remain slow.
We have therefore decided to regenerate an old technique that does not rely on PCR and that therefore obviates all the above problems. Few people around know this old technique, since PCR took over practically all experiments with DNA. The old technique is called Southern Blot. It is perfectly suited for this case. XiaoChu used to do this technique many years ago before PCR became dominant. She is able to revive it, and she is working on it.
I have concluded that for the longer term it would be best to establish this new (old) technique. Though it is on the surface a slower method than PCR-based methods, given the special problems of PCR in our current testing, it will end up being much faster than our turnaround now given the countless repeats and controls we have to do now.”
He goes on to confirm that the completed tests done in the initial control sample, are robust results, but the length of time taken to achieve them was due to the above issues.
Therefore, we are awaiting news that the new (old) method of testing is ready. As soon as we receive that, we will start to invite test submissions, as outlined in our previous update.
We are aware that the waiting is frustrating and thank you for bearing with us. For the long term, we want a test that is robust, reliable and the fastest turnaround possible and this early development work will give us that.
Test results can be found here.