A type of gene therapy called RNA interference (RNAi) is being investigated to treat Huntington's Disease - a disease where a misfolded protein forms clump in neural tissue. The techniques involve synthesizing short sequences of RNA (siRNA or small interfering RNA) that forms base pairs with the mRNA that codes for this protein. Why in theory would this strategy work to combat this disease and what is the largest obstacle that scientists have to overcome to make this strategy more successful.