Studies in families with frontotemporal dementia (FTD) [34] or frontotemporal lobar dementia (FTLD) found that PLOSL-associated TREM2 variants T66 M [35, 36], W198X [37], Q33X and Y38C [36] in either homozygosity or heterozygosity could also cause FTD [35–37] (Fig. 1). This evidence concerns the gene TYROBP and frontotemporal dementia.