Deficiency in PGRN levels is associated with development of neurodegenerative disease, including FTD subtypes with a mutation in C9ORF72 (TDP type A/B) [6] and in GRN (TDP type B) [3], and is linked to lysosomal dysfunction and TDP-43 aggregation [42]. The gene discussed is GRN; the disease is frontotemporal dementia.