Granulins are a family of secreted glycosylated peptides that are cleaved from a single precursor protein with 7.5 repeats of a highly conserved 12-cysteine granulin/epithelin motif. Progranulin (PGRN) is processed into granulin and then into a variety of active 6-kDa peptides (granulin A-G) that have possible cytokine-like activities with a role in inflammation, wound repair and tissue remodeling. Granulins are highly expressed in myelogenous leukemic cell lines of promonocytic, promyelocytic and proerythroid lineages. Defects in progranulin are the cause of ubiquitin-positive frontotemporal dementia (UP-FTD), the second most common cause of dementia in people under the age of 65 years.