Although a growing list of mutations responsible for ALS and FTD impinge on many aspects of RNA metabolism and protein homeostasis (recently reviewed in Taylor et al., 2016; Webster et al., 2017), in this mini-review, we focus on the subset of disease-causing RBPs that are hnRNPs, namely TDP-43, FUS, hnRNP A1, hnRNP A2B1, MATR3, and TIA1. The gene discussed is MATR3; the disease is frontotemporal dementia.