GRN and frontotemporal dementia: Progranulin (PGRN) is a highly-conserved protein and widely known to be one of the main genetic causes of frontotemporal dementia (FTD)(Baker et al. 2006; Cruts et al. 2006; Olney et al. 2017; van Swieten and Heutink 2008), a primary form of early-onset dementia.