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The gard protein

January 19, 2014

Huntington's Disease Youth Organization

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The gard protein

Q. How could the gard protein be inevitable in taking down hd and would it have any side effects ? also could the protein make hd worse?

Keir, Teen, Scotland

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A. Dear Keir,

Thanks for your question. Your answer this requires a lot of science. The underlying problem in HD is that the gene (the inheritance particle) that ultimately makes a natural chemical or protein called Huntington is faulty. The faulty gene causes HD.

Everyone has 2 genes (one from each parent) that ultimately makes the Huntington protein through another natural chemical called RNA.

That is, the sequence is gene makes RNA makes Huntington protein.

In HD one of the genes is faulty and this causes the disease. Normal Huntington genes have less than 36 CAG counts. Genes that cause HD have 36 or more CAG counts. Most people with HD have 40 or more CAG counts on the Huntington gene. We can test for this number with a blood test.

We still don’t know exactly why too high a CAG count causes HD, but it is certainly the case that the fault in the gene is the ultimate cause of HD and that the Huntington protein becomes toxic when there are 36 or more CAGs.

That is, in HD the sequence is faulty gene makes faulty RNA makes toxic protein that causes HD.

At present there are no effective treatments that stop or slow down HD, but there has been an explosion in our understanding of how & why a faulty gene causes HD. There is a good chance that over the next few years there might be effective treatments for HD, but whether they act on the gene, the RNA, the protein or a combination of these is too early to say.

I hope this answers your question

Andrew Churchyard, HD Specialist