PRMT5 is a histone methyltransferase that exhibits methylation activity toward H4-R3. PRMT5 is a critical regulatory-protein linked to genome organization, cell cycle regulation, and stem cell differentiation. PRMT5 transfers methyl groups from S-adenosylmethoinine (SAM) to form mono and symmetric di-methylated arginine residues in histone proteins, transcription factors, and other regulatory proteins. Given its regulatory function, PRMT5 is believed to contribute to tumorigenesis. Its dysregulated activity has been associated with many cancers including lymphomas, lung, and breast cancer. Additionally, PRMT5 has been linked to other diseases including kidney and heart disease as well as neurological disorders such as Huntington’s and Alzheimer’s diseases.