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Huntington’s breakthrough a step forward for A-T

There has been a lot of publicity in the media about a break-through in treating Huntington’s disease, and its potential for treating other neuro-degenerative conditions. As A-T is a neurodegenerative condition, people have been asking about its significance for research into A-T.

The answer is a mixed one. In Huntington’s disease, the faulty gene produces a protein which causes the damaging effects of the condition. The gene tells the cell to produce this protein by means of a messenger molecule. The drug, which is a strand of DNA called an ‘antisense oligonucleotide’ attaches itself to this messenger molecule and destroys it before the damaging protein is made.

In A-T however, rather than a damaging protein to be silenced; rather, the problems are caused by the fact that a protein, the ATM protein, is missing. It would therefore seem that there is no immediate opportunity to make use of this approach.

However, work by Steve Jackson in Cambridge and funded by the A-T Society, which he described at our Family Weekend in October has identified a couple of genes that when turned off appear to mitigate some of the effects of A-T. There is more work to be done on this but there is certainly a theoretical potential that this approach might be brought to bear on these genes. This is something that we have started talking to Steve about.

And there are a number of other positives to take out of this.

All advances in treating neurodegenerative conditions tell us more about the way the brain functions, and thus how problems can be treated. This research is likely to stimulate more research on conditions which are more obviously parallel to Huntington’s disease (for instance Alzheimer’s and Parkinson’s diseases) which may in turn throw up more potential approaches.

It is also extremely encouraging to see that this artificially produced strand of DNA can be introduced safely into the brain. There have been concerns that doing this might cause meningitis or other problems.

One of the issues for potential gene therapies in A-T is that the ATM molecule could not be injected into the bloodstream, as it is too large to pass through the so called blood-brain barrier. In this treatment, the drug was injected into the spino-cerebellar fluid and was then taken up in the brain.

In short, while not offering immediate answers to treating A-T, this breakthrough is a very positive step forward for A-T and for all other neurodegenerative conditions.