The DNA of every cell in our body contains the genes inherited from our parents and plays a crucial role in health and disease. While changes in the DNA itself are linked to monogenic diseases, they often fail to explain complex disorders such as neurodegenerative diseases. This can potentially be explained by additional layers of gene regulation known to be stored “above” the DNA, at the epigenetic level. Over the last years, this relatively young research field has shown that molecular structures packaging DNA in the cell nucleus influence gene activity. The DNA itself as well as its packaging structure, the so-called chromatin, can be chemically modified in many ways and is highly dynamic. With these findings, chromatin appears to be a central interface between genes and the environment, and the development and progression of diseases could be decisively influenced by epigenetic changes. Our research group investigates which epigenetic modifications are associated with complex neurological diseases – in particular Parkinson’s and Huntington’s – and how environmental factors and aging have modulating effects on them. Here, I will give an overview of current projects and highlight key findings of our work.