The invention relates to the treatment of Huntingtons disease (HD) using the Clustered- Regularly Interspaced Short Palindromic Repeats (CRISPR) system. This technology offers the possibility to design a small RNA (sg RNA), which is incorporated into a CRISPR- associated protein (Cas9) to recognize and induce DNA double-strand breaks at a specific target location. In the context of HD, this allows to block the expression of the mutant huntingtin or repair the CAG expansion causing the disease.