TREM2 and frontotemporal dementia: Less common causal genes such as those for valosin-containing protein (VCP), chromatin-modifying protein 2B (CHMP2B), TAR-DNA-binding protein 43 (TARDBP), fused in sarcoma (FUS), coiled-coil-helix-coiled-coil-helix domain-containing 10 (CHCHD10) and triggering receptor expressed on myeloid cells 2 (TREM2) are known to contribute to <5% of all FTD cases [10,13,14].