Furthermore, aging is associated with increased cytosolic iron, which can promote the oxidation of dopamine to the neurotoxic species dopamine quinone (DAQ).67 DAQ has been detected in PD-relevant cellular models.68 While the direct link needs further elucidation, it is possible that poor dopamine regulation caused by declining SIRT1 could increase DAQ formation, contributing to the neurodegenerative cascade in PD.66 The gene discussed is SIRT1; the disease is Parkinson disease.