In a C. elegans-based HD model, chronic exposure to copper, zinc, or their mixture can cause neurodegeneration by increasing the aggregation of polyQ protein in the muscles and neurons.568 Neuronal zinc finger protein (ZFP) transcriptional repressors can significantly reduce mutant HTT and rescue HD-associated behavioral and molecular phenotypes.569. The gene discussed is ZKSCAN7; the disease is Huntington disease.