The only study describing iPSC microglial cells from ALS or FTD patients was reported by Almeida et al. who showed that PGRN FTD patient microglial cells exhibit progranulin haploinsufficiency, but do not show the deficits in serine/threonine kinase S6K2 observed in iPSC neurons from the same patients (Almeida et al., 2012). Here, GRN is linked to frontotemporal dementia.