Recently, cases with homozygous mutations in TREM2 have been described to present atypical phenotypes resembling behavioral variant frontotemporal dementia (bvFTD) and lacking stage (2) of the clinical picture described previously (Chouery et al., 2008; Giraldo et al., 2013; Guerreiro et al., 2013b). The gene discussed is TREM2; the disease is behavioral variant of frontotemporal dementia.