So now we know that normal (wild-type) huntingtin has a definite purpose that mutant huntingtin cannot serve. I don't know if that means that mutant hungtingtin does or does not also do additional damage on its own in addition to not performing the normal function.
I asked Ken Pidcock about this research and this is the answer he gave me (I hope he doesn't mind my sharing it with you).
"I've read the Zuccato et al. paper with interest. I was familiar with the group from an earlier review summarizing evidence for a loss-of-function component to HD. Their Science report goes a long way toward clarifying the process of HD pathogenesis, in particular, the tissue-specific impact of the mutation.
As to the impact on therapy development, I think this work supports current directions. There have been animal studies suggesting a beneficial effect of BDNF supplementation, and that avenue may receive increased attention in response to this report. My personal bias remains toward discovery of drugs or biologicals aimed at interfering with the activity of mutant huntingtin in its interaction with wild-type huntingtin and other proteins.
Zuccato et al. affirm that therapeutic research is proceeding in the right direction. That's great news."
