A recent study conducted by Zhang et al. (2019) showed, by analyzing the amplitude of low-frequency fluctuation, that an alpha-synuclein (SNCA) gene polymorphism (rs894278) and PD status interactively affect the brain activity of PD patients and controls, but it did not focus on the cognitive alterations that make up PD-MCI. This evidence concerns the gene SNCA and Parkinson disease.