Potential future treatment for Huntington's disease?

"You know the last day was better than the next one's going to be." ;(

One thing I don't quite understand is how this breakthrough can help find treatment for other neurodegenerative diseases such as Parkinson's and Alzheimer's. While the cause of Huntington's is quite clear (i.e. an error in the huntingtin gene) this is not the case for Parkinson's for example. Most researchers BELIEVE that Parkinson's is caused by a combination of genetic and environmental factors but there are only hypotheses (i.e. the Braak theory, threshold theory, etc.)

Maybe the the article refers to the fact that the breakthrough could lead to developments in reducing alpha synuclein levels in the brain which most researchers agree is what treatment for Parkinson's should be aimed at. But even if a treatment is developed that targets a GENE which may code for alpha synuclein (the function of which is unknown), will this stop Parkinson's being developed later in life?

Sorry I kind of strayed from the Huntington's topic.

EDIT: Nvm, I just read this:

"...But Prof Mallucci, who is the associate director of UK Dementia Research Institute at the University of Cambridge, cautioned it was still a big leap to expect gene-silencing to work in other neurodegenerative diseases.

She told the BBC: "The case for these is not as clear-cut as for Huntington's disease, they are more complex and less well understood..."