We focus on five genes—Parkin (PRKN), Leucine Rich Repeat And Ig Domain Containing 2 (LINGO2), Microtubule Associated Protein Tau (MAPT), alpha-Synuclein (SNCA), and Amyloid Beta Precursor Protein (APP)—which may be relevant to neurological diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), or related disorders such as essential tremor (ET). This evidence concerns the gene SNCA and essential tremor.