BDNF and Huntington disease: For example, brain-derived neurotrophic factor (BDNF), an NRSF-target gene that is essential for neuronal survival, plasticity, and dendritic growth, is repressed in HD due to the high level of NRSF in the nucleus and the formation of the repressor complex on the promoter of BDNF, ultimately resulting in neurodegeneration (Zuccato et al., 2003).