AFF2 and frontotemporal dementia: CRISPR-Cas9-mediated loss of AFF2/FMR2 (one of four human homologs of Lilli) specifically reduces the levels of C9ORF72 RNA, RNA foci, and DPR protein in iPSC-derived neurons from C9ORF72-ALS/FTD patients, and can rescue axonal degeneration and TDP-43 pathology 21.