METTL14 and frontotemporal dementia: We analyzed the public proteomic data from Answer ALS and NeuroLINC, and found that the expression levels of m6A pathway components, especially the methyltransferases METTL3 and METTL14 in the “writer” complex, were markedly downregulated in C9ORF72-ALS/FTD patient-derived induced pluripotent stem cell (iPSC)-differentiated spinal neurons (iPSNs) (Fig. 1a and Extended Data Fig. 1a,b).